diff --git a/assets/images/originals/gasgiant-shop-02.png b/assets/images/originals/gasgiant-shop-02.png
new file mode 100644
index 0000000..0f011d6
Binary files /dev/null and b/assets/images/originals/gasgiant-shop-02.png differ
diff --git a/data/gates.json b/data/gates.json
index 9169c8a..1297ad5 100644
--- a/data/gates.json
+++ b/data/gates.json
@@ -14,5 +14,18 @@
   "anchorTetherLevel": 1,
   "barrenDistance": 8192,
   "typeLabel": "Jump Gate",
-  "theme": { "color": "#5fd4ff" }
+  "theme": { "color": "#5fd4ff" },
+  "activation": {
+    "_comment": "ACTIVATION (the SYSTEM research category — js/research/SystemCategory.js builds the per-system tree from this): '{system} Map' is granted the moment the player is in the system (duration 0 — 'starting'), and 'Unlock {system} Jumpgates' (researchDuration, in research.timeUnit seconds) becomes researchable once EVERY NAV point of the system is discovered (the central body, all planets, all space stations, all jump gates — the scene's discoverable set minus the asteroid clusters; data/game.json → discovery.distance). Completing it activates the system's gates AND the return gates in the systems they connect to — and per the ACTIVITY rule above, each activated gate anchors a level-`tetherLevel` tether at its own position (a TETHER ANCHOR in its own right; that tether saves/restores with the run's tether list). The label/description copy is templated: `{system}` is replaced with the system name.",
+    "researchDuration": 45,
+    "tetherLevel": 1,
+    "mapTech": {
+      "label": "{system} Map",
+      "description": "Added the Solar System of {system} to the onboard NAV System. Discover all NAV points to unlock the system Jumpgates."
+    },
+    "gatesTech": {
+      "label": "Unlock {system} Jumpgates",
+      "description": "With system NAV data complete, we have enough information to plot courses through this system's jumpgates."
+    }
+  }
 }
diff --git a/data/research.json b/data/research.json
index aba1243..8161062 100644
--- a/data/research.json
+++ b/data/research.json
@@ -5,8 +5,10 @@
   "maxConcurrent": 1,
   "defaultCategory": "exploration",
   "categories": [
-    { "id": "exploration", "label": "Exploration", "accent": "#00e5ff" }
+    { "id": "exploration", "label": "Exploration", "accent": "#00e5ff" },
+    { "id": "system", "label": "System", "accent": "#5fd4ff", "dynamic": true }
   ],
+  "_dynamic": "A category flagged `dynamic: true` has NO data/research/<id>.json — its tree is built at runtime per situation (js/research/SystemCategory.js: one tech pair per solar system, named after the system the player is in — its Map tech is granted on entry, its jumpgate tech researchable once every NAV point — planets, space stations, jump gates — is discovered, and activation flips the gates on, here and in the linked systems' return gates). Static categories keep the one-file-per-category rule; the tests exempt dynamic ones from the tree-file check.",
   "video": {
     "_comment": "The console's left-panel feed: loops muted while the window is open. aspect is [w, h] — the file is 544×800 (a 2:3 portrait).",
     "file": "assets/videos/research-computer.mp4",
diff --git a/dev/jumpgate.test.mjs b/dev/jumpgate.test.mjs
index c3dcc31..f6ccf44 100644
--- a/dev/jumpgate.test.mjs
+++ b/dev/jumpgate.test.mjs
@@ -39,6 +39,13 @@ class GameObject {
   add(o) { this.children.push(o); return this; }
   remove(o) { this.children = this.children.filter((c) => c !== o); return this; }
   removeChildren() { this.children.length = 0; return this; }
+  removeAll(destroy = false) {
+    // Phaser v4 Container API (JumpGate.destroy relies on it): detach all
+    // children, destroying them when asked.
+    for (const c of this.children) if (destroy) c.destroy?.();
+    this.children.length = 0;
+    return this;
+  }
   setOrigin() { return this; }
   setDepth() { return this; }
   setAlpha(a) { this.alpha = a; return this; }
diff --git a/dev/research-builds.test.mjs b/dev/research-builds.test.mjs
index 1f64973..8ef6fb4 100644
--- a/dev/research-builds.test.mjs
+++ b/dev/research-builds.test.mjs
@@ -54,9 +54,15 @@ check('research: categories is a non-empty array', Array.isArray(research.catego
 check('research: every category has id/label/accent', research.categories.every((c) => typeof c.id === 'string' && typeof c.label === 'string' && hex.test(c.accent ?? '')));
 check('research: defaultCategory names a real category', (research.categories ?? []).some((c) => c.id === research.defaultCategory));
 
-// every category in the registry has its own tree file in the manifest
-const missing = research.categories.filter((c) => !manifest.files.includes(`research/${c.id}.json`));
-check('research: every registered category has a tree file', missing.length === 0);
+// every STATIC category in the registry has its own tree file in the
+// manifest. A category flagged `dynamic: true` (currently: `system`)
+// has NO file — its tree is built at runtime (js/research/SystemCategory.js,
+// one tech pair per solar system); dev/system-category.test.mjs pins that
+// side of the contract.
+const missing = research.categories.filter((c) => !c.dynamic && !manifest.files.includes(`research/${c.id}.json`));
+check('research: every static registered category has a tree file', missing.length === 0);
+check('research: the SYSTEM category is registered (per-solar-system techs)', research.categories.some((c) => c.id === 'system'));
+check('research: the SYSTEM category is flagged dynamic (built at runtime)', (() => { const c = research.categories.find((c) => c.id === 'system'); return c?.dynamic === true; })());
 
 // the video feed (a 2:3 portrait loop)
 check('research: video file configured', typeof research.video?.file === 'string' && research.video.file.length > 0);
@@ -72,7 +78,7 @@ check('exploration: nodes is a non-empty map', typeof nodes === 'object' && Obje
 check('exploration: starting ⊆ nodes', Array.isArray(exploration.starting) && exploration.starting.every((id) => nodes[id]));
 check('exploration: starts with Tether Level 1 (the first thing to research)', (exploration.starting ?? []).includes('tether_l1'));
 
-const ICON_NAMES = ['tether', 'anchor', 'signal', 'diamond']; // mirrors js/research/ResearchIcons.js
+const ICON_NAMES = ['tether', 'tether2', 'anchor', 'signal', 'diamond', 'map', 'gate']; // mirrors js/research/ResearchIcons.js
 let nodeFieldsOk = true;
 let requiresOk = true;
 let unlocksOk = true;
diff --git a/dev/system-category.test.mjs b/dev/system-category.test.mjs
new file mode 100644
index 0000000..fbb5699
--- /dev/null
+++ b/dev/system-category.test.mjs
@@ -0,0 +1,211 @@
+/**
+ * SYSTEM research category test (dev tool, run with Node — no browser):
+ *
+ *   node dev/system-category.test.mjs
+ *
+ * Pins the contract behind the per-solar-system tech tree (the console's
+ * SYSTEM tab — categories flagged `dynamic` in research.json, built at
+ * runtime by js/research/SystemCategory.js; copy + duration in
+ * data/gates.json → activation):
+ *   - config: the activation section (45 s research, the two tech's
+ *     label/description templates with their `{system}` placeholder);
+ *   - buildSystemTree: the tree contract (ids embed the system id, the
+ *     map tech granted on entry, the jumpgate tech gated by the chart),
+ *     checked through the REAL code path (ResearchModel issues/layout/
+ *     isAvailable — with the `available`/`lockNote` hooks) and
+ *     ResearchState (one project at a time, save/restore);
+ *   - the chart gate: navPointIds = the scene's discoverable set minus
+ *     the asteroid clusters; isNavComplete is the every-NAV-point rule;
+ *   - activation: activationKeys = the system's gates + the linked
+ *     systems' RETURN gates (pure, from the jump network alone);
+ *     applyActivation flips the content records idempotently.
+ */
+import { fileURLToPath } from 'node:url';
+import { dirname, join } from 'node:path';
+import fs from 'node:fs';
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+const root = join(__dirname, '..');
+const dataDir = join(root, 'data');
+const read = (name) => JSON.parse(fs.readFileSync(join(dataDir, name), 'utf8'));
+
+let failures = 0;
+const check = (label, cond) => {
+  console.log(`${cond ? '✔' : '✘ FAIL'}  ${label}`);
+  if (!cond) failures++;
+};
+
+// ----------------------------------------------------------------------
+// Config — the activation section (data/gates.json)
+// ----------------------------------------------------------------------
+const gates = read('gates.json');
+const research = read('research.json');
+
+check('gates: activation section present', !!gates.activation && typeof gates.activation === 'object');
+check('gates: researchDuration is a positive number (seconds — research.timeUnit)',
+  typeof gates.activation?.researchDuration === 'number' && gates.activation.researchDuration > 0);
+check('gates: the 45 s brief duration', gates.activation?.researchDuration === 45);
+check('gates: tetherLevel ≥ 1 (an activated gate anchors a tether — ACTIVITY)',
+  Number.isInteger(gates.activation?.tetherLevel) && gates.activation.tetherLevel >= 1);
+check('gates: mapTech label template names the system',
+  typeof gates.activation?.mapTech?.label === 'string' && gates.activation.mapTech.label.includes('{system}'));
+check('gates: mapTech description is the brief copy',
+  gates.activation?.mapTech?.description ===
+    'Added the Solar System of {system} to the onboard NAV System. Discover all NAV points to unlock the system Jumpgates.');
+check('gates: gatesTech label template names the system',
+  typeof gates.activation?.gatesTech?.label === 'string' && gates.activation.gatesTech.label.includes('{system}'));
+check('gates: gatesTech description is the brief copy',
+  gates.activation?.gatesTech?.description ===
+    "With system NAV data complete, we have enough information to plot courses through this system's jumpgates.");
+
+check('research: the SYSTEM category is registered + dynamic',
+  (() => { const c = research.categories?.find((c) => c.id === 'system'); return !!c && c.dynamic === true && typeof c.label === 'string'; })());
+
+// ----------------------------------------------------------------------
+// The REAL code path
+// ----------------------------------------------------------------------
+const { config } = await import('../js/config/Config.js');
+config.init({ research, gates });
+const {
+  SYSTEM_CATEGORY, MAP_NODE, GATES_NODE, systemNodeId,
+  buildSystemTree, navPointIds, isNavComplete, activationKeys, applyActivation,
+} = await import('../js/research/SystemCategory.js');
+const { issues, layoutTree, isAvailable, missingRequires, unlockIssues } = await import('../js/research/ResearchModel.js');
+const { ResearchState } = await import('../js/research/ResearchState.js');
+
+const SYS = 'S000042';
+const NAME = 'Kepler Reach';
+
+// A live chart check the tests can flip (the scene wires the same seam
+// to its Discovery state).
+let chartComplete = false;
+const tree = buildSystemTree({
+  systemId: SYS,
+  systemName: NAME,
+  accent: research.categories.find((c) => c.id === SYSTEM_CATEGORY)?.accent,
+  isComplete: () => chartComplete,
+});
+
+const mapId = systemNodeId(SYS, MAP_NODE);
+const gatesId = systemNodeId(SYS, GATES_NODE);
+
+// -- tree contract ------------------------------------------------------
+check('tree: id is the shared SYSTEM category', tree.id === SYSTEM_CATEGORY && SYSTEM_CATEGORY === 'system');
+check('tree: node ids embed the system id (unique per system)', mapId === `${SYS}_map` && gatesId === `${SYS}_gates`);
+check('tree: order + starting (the map tech first, granted on entry)',
+  JSON.stringify(tree.order) === JSON.stringify([mapId, gatesId]) && JSON.stringify(tree.starting) === JSON.stringify([mapId]));
+
+const map = tree.nodes[mapId];
+const gNode = tree.nodes[gatesId];
+check('tree: map tech — the brief label + copy',
+  map.label === 'Kepler Reach Map' &&
+  map.description === 'Added the Solar System of Kepler Reach to the onboard NAV System. Discover all NAV points to unlock the system Jumpgates.');
+check('tree: map tech — duration 0 (granted, never researched), no requires',
+  map.duration === 0 && JSON.stringify(map.requires) === JSON.stringify([]));
+check('tree: map tech — icon from the procedural glyph roster', map.icon === 'map');
+check('tree: gates tech — the brief label + copy',
+  gNode.label === 'Unlock Kepler Reach Jumpgates' &&
+  gNode.description === "With system NAV data complete, we have enough information to plot courses through this system's jumpgates.");
+check('tree: gates tech — 45 s, requires the map, the activation effect',
+  gNode.duration === 45 && JSON.stringify(gNode.requires) === JSON.stringify([mapId]) && gNode.effects?.activateGates === true);
+check('tree: map tech declares the gates tech in its unlocks', JSON.stringify(map.unlocks?.research ?? []) === JSON.stringify([gatesId]));
+
+check('tree: issues(tree) is clean', Array.isArray(issues(tree)) && issues(tree).length === 0);
+check('tree: unlockIssues(tree) is clean (mirror + build wiring agree)', unlockIssues(tree).length === 0);
+const layout = layoutTree(tree);
+check('tree: layout — 2 rows, map root → gates leaf', layout.rows === 2 && layout.level[mapId] === 0 && layout.level[gatesId] === 1);
+
+// -- the availability hooks (the chart gate) -----------------------------
+const state = new ResearchState();
+state.unlock(SYSTEM_CATEGORY, mapId); // entering the system grants the map
+
+check('hooks: the gates tech waits on the chart (map unlocked, chart incomplete)',
+  !isAvailable(tree, state, gatesId));
+check('hooks: missingRequires is EMPTY (the gate is the chart, not a require)',
+  JSON.stringify(missingRequires(tree, state, gatesId)) === JSON.stringify([]));
+check('hooks: lockNote explains the locked gates tech',
+  typeof tree.lockNote(state, gatesId) === 'string' && tree.lockNote(state, gatesId).includes('KEPLER REACH'));
+check('hooks: lockNote is quiet on the map tech + when the chart is complete',
+  tree.lockNote(state, mapId) === null && (chartComplete = true) === true && tree.lockNote(state, gatesId) === null);
+
+chartComplete = true;
+check('hooks: chart complete → the gates tech is researchable', isAvailable(tree, state, gatesId));
+
+// -- the full run: one project at a time, save/restore -------------------
+state.start(SYSTEM_CATEGORY, gatesId, 45_000, 0);
+check('run: the in-flight project is the gates tech', state.getActive()?.id === gatesId);
+check('run: a second project is refused (one at a time)', state.start(SYSTEM_CATEGORY, gatesId, 1000, 0) === false);
+const saved = state.toJSON(20_000); // saved 20 s into the 45 s project
+const restored = new ResearchState();
+for (const k of saved.unlocked) restored.unlock(...k.split('::'));
+restored.restoreActive(saved.active, 900_000); // reloaded later
+check('run: save carries the remaining time (45 s − 20 s = 25 s)', saved.active?.remainingMs === 25_000);
+check('run: restore keeps the project in flight (25 s left)',
+  restored.getActive()?.id === gatesId && restored.progress(900_000).fraction < 1 && restored.progress(925_000).fraction >= 1);
+
+// -- the chart gate: NAV points + completion ------------------------------
+const content = {
+  name: NAME,
+  type: 'anchored',
+  planets: [{ name: 'K-1' }, { name: 'K-2' }],
+  settlements: [
+    { id: `${SYS}-s1`, anchor: { type: 'space' } },
+    { id: `${SYS}-s2`, anchor: { type: 'planet' } }, // planet-anchored — NOT a free-space station
+  ],
+  jumps: [{ id: `${SYS}-j1`, to: 'S000043' }, { id: `${SYS}-j2`, to: 'S000044' }],
+  asteroids: [{ id: `${SYS}-a1` }], // clusters are objects, not NAV points
+};
+check('nav: the NAV points = central body + planets + space stations + gates',
+  JSON.stringify(navPointIds(content)) === JSON.stringify(['home', 'K-1', 'K-2', `${SYS}-s1`, `${SYS}-j1`, `${SYS}-j2`]));
+
+const makeDiscovery = (found) => {
+  const set = new Set(found);
+  return { isDiscovered: (_sys, id) => set.has(id) };
+};
+check('nav: incomplete while any NAV point is undiscovered',
+  isNavComplete(makeDiscovery(['home', 'K-1', 'K-2', `${SYS}-s1`, `${SYS}-j1`]), SYS, content) === false);
+check('nav: complete once EVERY NAV point is discovered',
+  isNavComplete(makeDiscovery(['home', 'K-1', 'K-2', `${SYS}-s1`, `${SYS}-j2`, `${SYS}-j1`]), SYS, content) === true);
+check('nav: a missing discovery state never counts as complete', isNavComplete(null, SYS, content) === false);
+
+// -- activation: the system's gates + the linked systems' RETURN gates ----
+const galaxy = {
+  jumpNetwork: {
+    gates: new Map([
+      [SYS, ['S000043', 'S000044']],
+      ['S000043', [SYS]], // the gate in 43 jumps BACK to the system
+      ['S000044', ['S000045']], // the gate in 44 does NOT jump back (one-way shortcut)
+      ['S000045', ['S000044']],
+    ]),
+  },
+};
+check('activation: the keys = the system gates + the return gates that exist',
+  JSON.stringify(activationKeys(galaxy, SYS)) === JSON.stringify([`${SYS}>S000043`, `S000043>${SYS}`, `${SYS}>S000044`]));
+check('activation: completing the linked systems gates reaches back (the return gate)',
+  JSON.stringify(activationKeys(galaxy, 'S000043')) === JSON.stringify([`S000043>${SYS}`, `${SYS}>S000043`]));
+check('activation: no galaxy / no gates → no keys (defensive)',
+  JSON.stringify(activationKeys(null, SYS)) === JSON.stringify([]) &&
+  JSON.stringify(activationKeys({ jumpNetwork: {} }, SYS)) === JSON.stringify([]));
+
+// applyActivation flips the right records, idempotently
+const flipContent = (active = false) => ({
+  jumps: [
+    { id: `${SYS}-j1`, to: 'S000043', active },
+    { id: `${SYS}-j2`, to: 'S000044', active },
+    { id: `${SYS}-j3`, to: 'S000099', active: true }, // already on
+  ],
+});
+{
+  const c = flipContent();
+  const activated = new Set([`${SYS}>S000043`]);
+  const n1 = applyActivation(c, SYS, activated);
+  const n2 = applyActivation(c, SYS, activated); // again — nothing new
+  check('activation: flips exactly the activated gates (not the others, not the already-on)',
+    n1 === 1 && n2 === 0 && c.jumps[0].active === true && c.jumps[1].active === false && c.jumps[2].active === true);
+  check('activation: other systems stay untouched (a key of a different system)',
+    applyActivation(flipContent(), 'S000099', new Set([`${SYS}>S000043`])) === 0);
+}
+
+// ----------------------------------------------------------------------
+console.log(failures === 0 ? '\nall checks passed ✔' : `\n${failures} check(s) FAILED ✘`);
+process.exit(failures === 0 ? 0 : 1);
diff --git a/docs/PROJECT_NOTES.md b/docs/PROJECT_NOTES.md
index d635d9f..b0a6f9a 100644
--- a/docs/PROJECT_NOTES.md
+++ b/docs/PROJECT_NOTES.md
@@ -279,11 +279,15 @@ collide). **Barren systems** (no anchors — the `objectCount` → 0 stops)
   get their single gate on the star→destination ray at `barrenDistance`
   (8192 px) instead. Every gate record carries `active: false` — gates
   are DORMANT until activated (the entity renders dim, field still);
-  activation is the seam for the tether mechanic: an activated gate
+  activation is the SYSTEM research category's jumpgate tech completing
+  (the Research section below): the system's gates go live plus the
+  return gates in the systems they connect to, and each activated gate
   anchors a level-1 tether so the player can leave. A gate's `rotation`
   is the bearing from the gate to its
   destination star — the art (twin-pylon portal, `js/entities/JumpGate.js`
-  — procedural, Station.js-style) faces where it jumps.
+  — procedural, Station.js-style) faces where it jumps; the entity's
+  `activate()` lifts the dormant dimming (the anchor tether comes from
+  the scene).
 - **In the scene** — GameScene builds the gates as solid world objects
   (the ship keeps `gates.shipClearance` from them, autopilot flies to
   their rim), discoverable (compass arrows + toast, in the gate cyan
@@ -373,6 +377,37 @@ only present when the tech is researchable and nothing is in progress.
   **Add a category = one file + one line in `research.json → categories`
   + one line in `data/manifest.json`.**
 
+**The SYSTEM category (dynamic — per solar system):** one category is
+flagged `dynamic: true` in `research.json → categories` — it has **no**
+data file; its tree is built at runtime for the system the player is in
+(`js/research/SystemCategory.js` → `buildSystemTree`), so its two techs
+are NAMED after that system. Node ids embed the system id
+(`S000012_map`, `S000012_gates`) so a run can chart many systems in the
+one shared category without collisions:
+- **`{System} Map`** — `duration: 0`, in `starting`: granted the moment
+  the player is in the system (`GameScene._onEnterSystem()` unlocks it —
+  the jump mechanic, when it lands, calls the same seam on every
+  arrival). Copy: *Added the Solar System of {system} to the onboard
+  NAV System. Discover all NAV points to unlock the system Jumpgates.*
+- **`Unlock {System} Jumpgates`** — requires the map; researchable once
+  **every NAV point of the system is discovered** (the central body, all
+  planets, all space stations, all jump gates — the scene's discoverable
+  set minus the asteroid clusters); 45 s
+  (`data/gates.json → activation.researchDuration`). Completing it
+  activates the system's gates **and the return gates in the systems
+  they connect to** (pure, from the jump network alone —
+  `activationKeys`), and per the gate ACTIVITY rule each activated gate
+  anchors a level-1 tether at its own position.
+
+The gates node's chart gate is an **availability HOOK**, not a `requires`
+edge (its requires are all met at grant — the gate is live-world state):
+the tree object carries optional `available(state, id)` / `lockNote(state, id)`
+functions, consulted by `ResearchModel.isAvailable` and the console's
+LOCKED readout. Static trees have no hooks. The label/description copy
+and the duration live in `data/gates.json → activation` (templated —
+`{system}` is replaced with the system name); the tests exempt
+`dynamic: true` categories from the one-file-per-category rule.
+
 **The UNLOCKS space (research → everything else):** a tech unlocks more
 than follow-on tech. Each node's `unlocks` is the declaration side:
 - `unlocks.research` — the readable mirror of the children's `requires`
@@ -408,7 +443,17 @@ than follow-on tech. Each node's `unlocks` is the declaration side:
   contract: `unlocksOf` (normalize `{builds, research}`), `buildDefs`
   (builds.json → map, `_`-keys excluded), `unlockIssues(tree)` (mirror +
   build wiring), `buildIssues()` (every build `requires` id resolves).
-  Node-tested.
+  `isAvailable` also consults a tree's optional `available(state, id)`
+  hook (the dynamic SYSTEM category's chart gate). Node-tested.
+- `js/research/SystemCategory.js` — PURE (no Phaser): the dynamic
+  SYSTEM category. `buildSystemTree({systemId, systemName, accent,
+  isComplete})` (the per-system tree + the `available`/`lockNote`
+  hooks), `navPointIds(content)` (the chart's NAV points),
+  `isNavComplete(discovery, systemId, content)` (every NAV point
+  discovered), `activationKeys(galaxy, systemId)` (the system's gates +
+  the linked systems' return gates, from the jump network alone),
+  `applyActivation(content, systemId, keys)` (flip the records
+  idempotently). Node-tested by `dev/system-category.test.mjs`.
 - `js/research/ResearchState.js` — PURE: `unlock`, `isUnlocked`, `getActive`,
   `start`, `progress(time)`, `tick(time)` (→ array of completions),
   `restoreActive`, `toJSON(now)`/`fromJSON`. Node-tested.
@@ -423,28 +468,50 @@ than follow-on tech. Each node's `unlocks` is the declaration side:
   `_applyResearchEffects`, `_deckResearchBar`. The **effects seam** reads
   `node.effects`: `{ tether: { level: N } }` → `TetherField.setLevel(homeId, N)`
   + toast; `{ capability: "flag" }` → `scene.researchCapabilities.add(flag)`;
-  unknown shapes log and no-op. New effect kinds plug in there without
-  touching tree data.
+  `{ activateGates: true }` (SYSTEM category) → the system's gates + the
+  linked systems' return gates go ACTIVE (`_activateSystemJumpgates` — the
+  activation keys join the run's `activatedGates` set, the current
+  system's gate entities wake, and each activated gate anchors its
+  level-1 tether); unknown shapes log and no-op. New effect kinds plug in
+  there without touching tree data.
+- The SYSTEM category's world state is the run's **`activatedGates`** set
+  (activation keys `"<sysId>><destId>"`) — registry-backed like discovery
+  (`GameScene.create` reads it; `resetRunState` clears it on New Game,
+  `prepareLoad` restores it), and the anchored gate tethers save with the
+  run's tether list. On entry the scene flips the current system's gate
+  records BEFORE the gate entities build (the dormant look is baked at
+  construction), and anchors each activated gate's tether after the
+  field exists. `GameScene._onEnterSystem()` grants the map tech on
+  arrival (new run, load, and — when it lands — every jump landing).
+  The ResearchWindow takes the live tree via `systemTree` and re-paints
+  nodes live when a state flips under the open console (the chart
+  completes, a run starts).
 
 **Save:** `record.research = { unlocked: ["cat::id", …], active:
 {category, id, durationMs, remainingMs} | null }`. `remainingMs` is captured
 at save time; `restoreActive(spec, now)` rebuilds `startedAt` from the fresh
 `now`. A save from before research exists loads as fresh (no unlocks, no
-active run) — old saves keep working. No auto-save: research state persists
-on the next explicit player save (SavePanel), consistent with the rest of
-the game.
+active run) — old saves keep working. The SYSTEM category's activation keys
+ride `record.activatedGates` (an array of `"<sysId>><destId>"`; saves from
+before the category load as an empty set — gates stay dormant). No
+auto-save: research state persists on the next explicit player save
+(SavePanel), consistent with the rest of the game.
 
 **SFX:** begin → `construct`, complete → `discovery` (both existing
 `data/sfx.json` keys — there are no `research_begin`/`research_complete`
 keys). Open/close → `ui_window`/`ui_close`.
 
 **Verified:** `dev/research-builds.test.mjs` (manifest registration,
-research.json globals, the exploration tree's raw-JSON contract — DAG, node
+research.json globals — incl. the dynamic SYSTEM category's registration,
+the exploration tree's raw-JSON contract — DAG, node
 fields, effects — the real code path: ResearchModel layout/levels/determinism
 + the unlocks contract (unlocksOf/unlockIssues/buildIssues) +
 ResearchState start/tick/complete/restore round-trip, builds.json (the
 tether-l2 build, both sides of the gate, the template), actionbar.json).
-`dev/research-shot.html` + `dev/cdp-shot.mjs` open the window and start a
+`dev/system-category.test.mjs` (the gates.json activation contract, the
+per-system tree through the real code path — hooks, one-at-a-time,
+save/restore round-trip — the NAV-point rule, the activation keys +
+record flips). `dev/research-shot.html` + `dev/cdp-shot.mjs` open the window and start a
 run through CDP for a screenshot.
 
 ## Builds — the surface install (cost-based, one at a time)
diff --git a/js/entities/JumpGate.js b/js/entities/JumpGate.js
index 0162af2..89023f8 100644
--- a/js/entities/JumpGate.js
+++ b/js/entities/JumpGate.js
@@ -149,6 +149,20 @@ export class JumpGate extends Phaser.GameObjects.Container {
     if (!this.active) this.setAlpha(0.4);
   }
 
+  /**
+   * Flip to ACTIVE — the SYSTEM category's jumpgate research completes
+   * (js/research/SystemCategory.js; the scene's seam wakes every gate of
+   * the system plus the linked systems' return gates). The dormant
+   * dimming lifts and update() starts the field breathing. (Per
+   * data/gates.json → ACTIVITY the anchor tether comes from the scene —
+   * this entity only carries the live look.)
+   */
+  activate() {
+    if (this.active) return;
+    this.active = true;
+    this.setAlpha(1);
+  }
+
   /** The ring drifts; the field breathes. (GameScene.update drives this.) */
   update(time) {
     const t = time / 1000;
diff --git a/js/research/ResearchIcons.js b/js/research/ResearchIcons.js
index dcebdc7..a91802b 100644
--- a/js/research/ResearchIcons.js
+++ b/js/research/ResearchIcons.js
@@ -6,7 +6,7 @@
  */
 import { toColor } from '../utils/Color.js';
 
-export const ICON_NAMES = ['tether', 'tether2', 'anchor', 'signal', 'diamond'];
+export const ICON_NAMES = ['tether', 'tether2', 'anchor', 'signal', 'diamond', 'map', 'gate'];
 
 export function iconKey(name, color = 0x00e5ff) {
   const n = ICON_NAMES.includes(name) ? name : 'diamond';
@@ -136,6 +136,49 @@ export function ensureIcon(scene, name, color = 0x00e5ff) {
       ctx.stroke();
     }
     ctx.globalAlpha = 1;
+  } else if (n === 'map') {
+    // The SYSTEM category's chart glyph — a folded map sheet with a plotted
+    // route between two NAV points (the per-system '{System} Map' tech).
+    const w = 62,
+      h = 50,
+      x = cx - w / 2,
+      y = cy - h / 2;
+    ctx.beginPath();
+    ctx.roundRect(x, y, w, h, 7);
+    ctx.stroke();
+    // fold line
+    ctx.beginPath();
+    ctx.moveTo(cx, y);
+    ctx.lineTo(cx, y + h);
+    ctx.stroke();
+    // route: two plotted points + the line between them
+    ctx.beginPath();
+    ctx.moveTo(x + w * 0.22, y + h * 0.68);
+    ctx.lineTo(x + w * 0.78, y + h * 0.32);
+    ctx.stroke();
+    diamond(x + w * 0.22, y + h * 0.68, 5);
+    diamond(x + w * 0.78, y + h * 0.32, 5);
+  } else if (n === 'gate') {
+    // The SYSTEM category's jumpgate glyph — the ring + its inner aperture
+    // (+ the four aperture seams), like the world's gate entity minus field.
+    ctx.globalAlpha = 0.95;
+    ctx.beginPath();
+    ctx.arc(cx, cy, 44, 0, Math.PI * 2);
+    ctx.stroke();
+    ctx.globalAlpha = 1;
+    ctx.lineWidth = 3.5;
+    ctx.beginPath();
+    ctx.arc(cx, cy, 19, 0, Math.PI * 2);
+    ctx.stroke();
+    ctx.lineWidth = 5;
+    ctx.globalAlpha = 0.6;
+    for (const a of [0, Math.PI / 2, Math.PI, (3 * Math.PI) / 2]) {
+      ctx.beginPath();
+      ctx.moveTo(cx + Math.cos(a) * 28, cy + Math.sin(a) * 28);
+      ctx.lineTo(cx + Math.cos(a) * 37, cy + Math.sin(a) * 37);
+      ctx.stroke();
+    }
+    ctx.globalAlpha = 1;
   } else {
     // diamond — the default glyph
     ctx.beginPath();
diff --git a/js/research/ResearchModel.js b/js/research/ResearchModel.js
index 6cf0a96..b51b2d8 100644
--- a/js/research/ResearchModel.js
+++ b/js/research/ResearchModel.js
@@ -12,6 +12,10 @@
  * leaves take sequential slots in DFS order (data order of roots, then
  * children), each interior node sits at the mean of its children's columns —
  * a tidy, stable arrangement for a small tech tree.
+ * Optional tree hooks (dynamic categories, e.g. SystemCategory): a tree
+ * object may carry `available(state, id)` (extra availability gate,
+ * consulted by isAvailable) and `lockNote(state, id)` (the window's
+ * LOCKED reason when the node is gated but its requires are met).
  */
 import { config } from '../config/Config.js';
 
@@ -163,12 +167,19 @@ export function layoutTree(tree) {
  * Can this node be researched right now? (known + all parents researched +
  * not already researched.) `state` is a ResearchState (or anything with
  * isUnlocked(category, id)).
+ *
+ * A tree may also carry an optional `available(state, id)` predicate —
+ * an EXTRA availability gate evaluated after the requires check (the
+ * SYSTEM category uses it for its chart-completion gate; static trees
+ * have none). Pure: the predicate is data the caller supplies.
  */
 export function isAvailable(tree, state, id) {
   const n = tree.nodes[id];
   if (!n) return false;
   if (state.isUnlocked(tree.id, id)) return false;
-  return (n.requires ?? []).every((r) => tree.nodes[r] && state.isUnlocked(tree.id, r));
+  if ((n.requires ?? []).some((r) => !tree.nodes[r] || !state.isUnlocked(tree.id, r))) return false;
+  if (typeof tree.available === 'function' && !tree.available(state, id)) return false;
+  return true;
 }
 
 /** The parents this node is still missing (for the LOCKED readout). */
diff --git a/js/research/SystemCategory.js b/js/research/SystemCategory.js
new file mode 100644
index 0000000..3617782
--- /dev/null
+++ b/js/research/SystemCategory.js
@@ -0,0 +1,213 @@
+/**
+ * SystemCategory — the SYSTEM research category: the ONE per-solar-system
+ * tech tree (research.json → categories, flagged `dynamic: true`).
+ *
+ * Every other category reads its tree from data/research/<id>.json —
+ * static data, same for every run. The SYSTEM category is different by
+ * design: its tree is built at runtime from the system the player is
+ * currently in, so the two techs are NAMED after that system:
+ *
+ *   "{System} Map"                        granted on entry (duration 0,
+ *                                          in `starting` — the scene
+ *                                          unlocks it, ResearchState
+ *                                          "already owned")
+ *   └ "Unlock {System} Jumpgates"         requires the map + EVERY NAV
+ *                                          point of the system discovered
+ *                                          (the availability hook below);
+ *                                          45 s (data/gates.json →
+ *                                          activation.researchDuration);
+ *                                          completing it activates the
+ *                                          system's gates AND the return
+ *                                          gates in the systems they
+ *                                          connect to.
+ *
+ * Node ids embed the system id (`S000012_map`, `S000012_gates`) so a run
+ * can chart many systems in the one `system` category without collisions,
+ * and ResearchState's "category::id" keys stay unique per system.
+ *
+ * The tree carries two optional HOOKS the static trees don't need —
+ * ResearchModel consumes them (pure: the predicates are data the caller
+ * supplies, evaluated at paint time):
+ *   tree.available(state, id) — extra availability gate (the chart gate:
+ *     the jumpgate tech is researchable only while isComplete() holds);
+ *   tree.lockNote(state, id)  — the detail readout's LOCKED reason when
+ *     the node is gated but its `requires` are all met.
+ *
+ * Pure (no Phaser) — Node-testable (dev/system-category.test.mjs).
+ */
+import { config } from '../config/Config.js';
+
+/** The category id (data/research.json → categories[]). */
+export const SYSTEM_CATEGORY = 'system';
+
+/** The two node kinds. */
+export const MAP_NODE = 'map';
+export const GATES_NODE = 'gates';
+
+/** A system's tech node id — unique per system (the category is shared). */
+export function systemNodeId(systemId, kind) {
+  return `${systemId}_${kind}`;
+}
+
+const fillTemplate = (template, systemName) =>
+  String(template ?? '').split('{system}').join(systemName);
+
+/**
+ * Build the SYSTEM category's tree for one system.
+ *
+ * @param {object} o
+ * @param {string} o.systemId — the system record's id (node-id prefix)
+ * @param {string} o.systemName — the system name (labels + copy)
+ * @param {string} [o.accent] — the category accent (registry, research.json)
+ * @param {() => boolean} [o.isComplete] — live chart check: true once
+ *   EVERY NAV point of the system is discovered (the scene wires it to
+ *   its Discovery state; absent = the chart never completes)
+ * @returns {object} a ResearchModel tree (id/label/accent/nodes/order/
+ *   starting) + the optional `available` / `lockNote` hooks.
+ */
+export function buildSystemTree(o = {}) {
+  const systemId = String(o.systemId ?? '');
+  const systemName = String(o.systemName ?? systemId);
+  const mapId = systemNodeId(systemId, MAP_NODE);
+  const gatesId = systemNodeId(systemId, GATES_NODE);
+  const duration = Math.max(0, Number(config.get('gates.activation.researchDuration', 45)) || 0);
+  const isComplete = typeof o.isComplete === 'function' ? o.isComplete : () => false;
+
+  const chartLockedNote =
+    'NAV CHART INCOMPLETE — DISCOVER ALL PLANETS, STATIONS AND JUMP GATES OF ' +
+    systemName.toUpperCase();
+
+  const tree = {
+    id: SYSTEM_CATEGORY,
+    label: 'System',
+    accent: typeof o.accent === 'string' && o.accent ? o.accent : '#5fd4ff',
+    nodes: {
+      [mapId]: {
+        label: fillTemplate(config.get('gates.activation.mapTech.label', '{system} Map'), systemName),
+        description: fillTemplate(
+          config.get(
+            'gates.activation.mapTech.description',
+            'Added the Solar System of {system} to the onboard NAV System. Discover all NAV points to unlock the system Jumpgates.',
+          ),
+          systemName,
+        ),
+        icon: 'map',
+        duration: 0, // granted on entry — never researched
+        requires: [],
+        unlocks: { builds: [], research: [gatesId] },
+        effects: {},
+      },
+      [gatesId]: {
+        label: fillTemplate(config.get('gates.activation.gatesTech.label', 'Unlock {system} Jumpgates'), systemName),
+        description: fillTemplate(
+          config.get(
+            'gates.activation.gatesTech.description',
+            "With system NAV data complete, we have enough information to plot courses through this system's jumpgates.",
+          ),
+          systemName,
+        ),
+        icon: 'gate',
+        duration,
+        requires: [mapId],
+        unlocks: { builds: [], research: [] },
+        // The scene's effects seam reads this (GameScene._applyResearchEffects):
+        // activate the system's gates + the linked systems' return gates.
+        effects: { activateGates: true },
+      },
+    },
+    order: [mapId, gatesId],
+    starting: [mapId],
+  };
+
+  // The hooks (see the header) — the scene's live chart check drives both.
+  tree.available = (_state, id) => (id === gatesId ? isComplete() : true);
+  tree.lockNote = (_state, id) => (id === gatesId && !isComplete() ? chartLockedNote : null);
+  return tree;
+}
+
+/**
+ * A system's NAV points — the discovery ids the scene's
+ * discoverableObjects() uses for its discoverable set, minus the rocks
+ * (asteroid clusters are objects, not NAV points): the central body
+ * (every system — the scene's 'home' id, the player's home world in the
+ * starting system and the system's central world elsewhere), every
+ * planet (its name), every free-space station (its settlement id),
+ * every jump gate (its gate id).
+ *
+ * @param {object} content — a generated system content (ensureContent)
+ * @returns {string[]} the discoverable ids to check (order: stable)
+ */
+export function navPointIds(content) {
+  const ids = [];
+  ids.push('home'); // the central body — discoverable in every system
+  for (const p of content?.planets ?? []) if (p && typeof p.name === 'string') ids.push(p.name);
+  for (const s of content?.settlements ?? []) {
+    if (s && s.anchor?.type === 'space' && typeof s.id === 'string') ids.push(s.id);
+  }
+  for (const j of content?.jumps ?? []) if (j && typeof j.id === 'string') ids.push(j.id);
+  return ids;
+}
+
+/**
+ * Is the system fully charted? Every NAV point discovered
+ * (js/galaxy/Discovery.js — `discovery.isDiscovered(systemId, id)`).
+ * Vacuously true for a content with no NAV points (a degenerate
+ * one-system galaxy with no gates).
+ *
+ * @param {object} discovery — the scene's Discovery state
+ * @param {string} systemId
+ * @param {object} content
+ * @returns {boolean}
+ */
+export function isNavComplete(discovery, systemId, content) {
+  if (!discovery || typeof discovery.isDiscovered !== 'function') return false;
+  return navPointIds(content).every((id) => discovery.isDiscovered(systemId, id));
+}
+
+/**
+ * The activation keys one completed "Unlock {System} Jumpgates" grants:
+ * every gate in `systemId` (keyed "<systemId>><destination>") AND the
+ * RETURN gates in the systems those destinations connect back to —
+ * the gate in `<destination>` whose destination is `systemId`.
+ *
+ * Pure: computed from the jump network alone (no content generation).
+ *
+ * @param {object} galaxy — the Galaxy (reads galaxy.jumpNetwork.gates:
+ *   Map systemId → destination ids)
+ * @param {string} systemId
+ * @returns {string[]} activation keys (deduplicated, stable order)
+ */
+export function activationKeys(galaxy, systemId) {
+  const gates = galaxy?.jumpNetwork?.gates;
+  if (!gates || typeof gates.get !== 'function') return [];
+  const out = [];
+  const push = (k) => {
+    if (k && !out.includes(k)) out.push(k);
+  };
+  for (const dest of gates.get(systemId) ?? []) {
+    push(`${systemId}>${dest}`);
+    if ((gates.get(dest) ?? []).includes(systemId)) push(`${dest}>${systemId}`);
+  }
+  return out;
+}
+
+/**
+ * Flip a generated system's gate records to ACTIVE for every activation
+ * key in `activated` (the "<systemId>><destination>" keys). Idempotent;
+ * returns how many gates changed.
+ *
+ * @param {object} content — the system's generated content
+ * @param {string} systemId — content's system id (the cache key)
+ * @param {Set<string>} activated — the run's activation keys
+ * @returns {number}
+ */
+export function applyActivation(content, systemId, activated) {
+  let n = 0;
+  for (const j of content?.jumps ?? []) {
+    if (j && typeof j.to === 'string' && !j.active && activated?.has(`${systemId}>${j.to}`)) {
+      j.active = true;
+      n++;
+    }
+  }
+  return n;
+}
diff --git a/js/save/SaveData.js b/js/save/SaveData.js
index 2dc50ce..548f4cd 100644
--- a/js/save/SaveData.js
+++ b/js/save/SaveData.js
@@ -10,7 +10,14 @@
  *     ship: { x, y, heading, minerals },
  *     discovery: Discovery.toJSON(),
  *     reputation: Reputation.toJSON(),
- *     tethers: [{ id, x, y, level, label }],
+ *     tethers: [{ id, x, y, level, label }],   // incl. the activated
+ *                                                // gates' anchor tethers
+ *     activatedGates: ["<sysId>><destId>"],    // the SYSTEM research
+ *                                                // category's activation
+ *                                                // keys (registry-backed
+ *                                                // Set, replayed on load —
+ *                                                // gates + tethers re-form
+ *                                                // in GameScene.create)
  *     research: ResearchState.toJSON() | null,
  *     builds: BuildState.toJSON() | null,
  *     playTimeMs }
@@ -96,6 +103,12 @@ export function captureState(scene, now) {
     builds: scene.buildState
       ? scene.buildState.toJSON(buildNow)
       : null,
+    // The SYSTEM research category's activation keys (which jump gates —
+    // incl. other systems' return gates — the run has activated; the
+    // per-run world state GameScene keeps in its registry-backed set).
+    // Pre-system-category saves lack the field; the restore treats the
+    // absence as an empty set (old saves load).
+    activatedGates: Array.from(scene.activatedGates ?? []),
     playTimeMs: Math.round(scene.playTimeMs ?? 0),
   };
   const err = SaveManager.validateRecord(rec);
@@ -130,6 +143,14 @@ export function prepareLoad(registry, record) {
   registry.set('seed', seed);
   registry.set('discovery', Discovery.fromJSON(record.discovery ?? { distance: 540, bySystem: {} }));
   registry.set('reputation', Reputation.fromJSON(record.reputation));
+  // The SYSTEM category's activation keys (a save predating the category
+  // has no field → an empty set). GameScene.create() reads the set, flips
+  // the current system's gate content before its entities build, and
+  // anchors the gate tethers (data/gates.json → ACTIVITY).
+  registry.set(
+    'activatedGates',
+    new Set(Array.isArray(record.activatedGates) ? record.activatedGates : []),
+  );
   registry.set(PENDING_RESTORE_KEY, {
     ship: record.ship,
     tethers: Array.isArray(record.tethers) ? record.tethers : [],
@@ -152,12 +173,13 @@ export function consumeRestore(registry) {
 
 /**
  * "New Game" from the main menu: a fresh run must not inherit the
- * previous one's discovery state, its standing with the old galaxy, or a
- * half-staged restore.
+ * previous one's discovery state, its standing with the old galaxy, its
+ * activated jump gates, or a half-staged restore.
  */
 export function resetRunState(registry) {
   registry.set('discovery', null);
   registry.set('reputation', null);
+  registry.set('activatedGates', null);
   registry.set(PENDING_RESTORE_KEY, null);
 }
 
diff --git a/js/scenes/GameScene.js b/js/scenes/GameScene.js
index 5fce233..9d79d0c 100644
--- a/js/scenes/GameScene.js
+++ b/js/scenes/GameScene.js
@@ -33,6 +33,15 @@ import { CommsPanel } from '../ui/CommsPanel.js';
 import { ResearchWindow } from '../ui/ResearchWindow.js';
 import { ResearchState } from '../research/ResearchState.js';
 import { categories, loadCategory, isAvailable, buildDefs } from '../research/ResearchModel.js';
+import {
+  SYSTEM_CATEGORY,
+  MAP_NODE,
+  systemNodeId,
+  buildSystemTree,
+  isNavComplete,
+  activationKeys,
+  applyActivation,
+} from '../research/SystemCategory.js';
 import { BuildWindow } from '../ui/BuildWindow.js';
 import { BuildState } from '../build/BuildState.js';
 import { startingPairs } from '../build/BuildModel.js';
@@ -209,6 +218,23 @@ export class GameScene extends Phaser.Scene {
     this._pendingRestore = consumeRestore(this.registry);
     this.systemRecord = this.galaxy.currentSystem();
     this.systemContent = this.galaxy.ensureContent(this.systemRecord.id);
+    // JUMP GATE ACTIVATION (the SYSTEM research category —
+    // js/research/SystemCategory.js): the run's activation keys are
+    // per-run world state — registry-backed (like discovery: New Game
+    // clears it, a load restores it; js/save/SaveData.js). A gate the
+    // run activated — or whose RETURN the run activated from a linked
+    // system — flips on here, BEFORE the gate entities below read
+    // `active` (the dormant look is baked at construction); the gate
+    // tethers (data/gates.json → ACTIVITY) attach after the field exists
+    // (below) and save with the run's tether list.
+    this.activatedGates = this.registry.get('activatedGates') ?? null;
+    if (!this.activatedGates) {
+      this.activatedGates = new Set();
+      this.registry.set('activatedGates', this.activatedGates);
+    }
+    for (const j of this.systemContent.jumps ?? []) {
+      if (j && this.activatedGates.has(`${this.systemRecord.id}>${j.to}`)) j.active = true;
+    }
     // The home world's name — dealt from the planet name bank by the
     // generator (the starting system is the only one with a home world), so
     // it reads as a real place rather than a generic "Terra". Fallback keeps
@@ -351,6 +377,14 @@ export class GameScene extends Phaser.Scene {
       config.get('tether.homeLevel', 1),
       config.get('tether.homeLabel', '') || this.homeWorldName,
     );
+    // Each activated gate anchors its tether (data/gates.json → ACTIVITY:
+    // an active gate is a TETHER ANCHOR in its own right — the room to
+    // move in a barren system). Idempotent: add() replaces by id, and a
+    // save's tether list restores to the same ids.
+    const gateTetherLevel = Math.max(1, Math.floor(Number(config.get('gates.activation.tetherLevel', 1)) || 1));
+    for (const j of this.systemContent.jumps ?? []) {
+      if (j && j.active) this.tetherField.add(`gate:${j.id}`, j.x, j.y, gateTetherLevel, j.name ?? '');
+    }
     this.tetherToastAt = null;
 
     // Discovery: which objects the player has found (within discovery
@@ -477,8 +511,22 @@ export class GameScene extends Phaser.Scene {
       if (!tree) continue;
       for (const id of tree.starting) this.researchState.unlock(cat.id, id);
     }
+    // The SYSTEM category's live tree — built for the system the player is
+    // in (categories flagged `dynamic` in research.json have no data file):
+    // the '{System} Map' (granted on entry — _onEnterSystem below) and
+    // 'Unlock {System} Jumpgates' (chart complete → researchable → the
+    // gates + the linked systems' return gates go live). js/research/
+    // SystemCategory.js; copy + duration in data/gates.json → activation.
+    const sysCat = categories().find((c) => c.id === SYSTEM_CATEGORY);
+    this.systemTree = buildSystemTree({
+      systemId: this.systemRecord.id,
+      systemName: this.systemRecord.name,
+      accent: sysCat?.accent,
+      isComplete: () => this.isSystemNavComplete(),
+    });
     this.researchWindow = new ResearchWindow(this, {
       state: this.researchState,
+      systemTree: this.systemTree,
       onResearch: (catId, id) => this.beginResearch(catId, id),
     });
     // deck progress bar — drawn over the RESEARCH button while a project runs
@@ -522,6 +570,13 @@ export class GameScene extends Phaser.Scene {
       this._pendingRestore = null;
     }
 
+    // Entering a system charts it: the SYSTEM category's '{System} Map'
+    // tech (duration 0) is owned on arrival — a new run gets the starting
+    // system's, a load re-asserts the saved system's (the restore above
+    // replaced the unlocked set), and the jump mechanic (when it lands)
+    // calls _onEnterSystem() on every arrival.
+    this._onEnterSystem();
+
     // ---- DEEP SCAN (the deck's SCAN button) -------------------------------
     // The ship's sonar pulse (js/scan/ScanPulse.js): a charge at the hull,
     // then an omnidirectional wavefront expanding across the TETHER REGION
@@ -1729,7 +1784,7 @@ export class GameScene extends Phaser.Scene {
       });
       return;
     }
-    const tree = loadCategory(catId);
+    const tree = this._treeFor(catId);
     const node = tree?.nodes?.[id];
     if (!node) return;
     if (!isAvailable(tree, state, id)) {
@@ -1762,11 +1817,72 @@ export class GameScene extends Phaser.Scene {
     const state = this.researchState;
     if (!state) return;
     state.unlock(catId, id);
-    const node = loadCategory(catId)?.nodes?.[id];
+    const node = this._treeFor(catId)?.nodes?.[id];
     if (node?.effects) this._applyResearchEffects(node.effects, node);
     this._completeResearchFx(catId, id, node);
   }
 
+  /** The tree for a category: the SYSTEM category's live per-system tree,
+   * or the static file tree (data/research/<id>.json — null if missing). */
+  _treeFor(catId) {
+    if (this.systemTree && catId === this.systemTree.id) return this.systemTree;
+    return loadCategory(catId);
+  }
+
+  /** Entering a system begins its NAV chart: the SYSTEM category's
+   * '{System} Map' tech is granted (duration 0 — never researched via the
+   * console). Idempotent — create() calls it for the starting system (and
+   * again after a load, whose restore replaced the unlocked set); the
+   * jump mechanic (when it lands) calls it on every arrival. */
+  _onEnterSystem() {
+    if (!this.researchState || !this.systemRecord) return;
+    this.researchState.unlock(SYSTEM_CATEGORY, systemNodeId(this.systemRecord.id, MAP_NODE));
+    this.researchWindow?.refresh();
+  }
+
+  /** The SYSTEM category's chart gate: every NAV point of the current
+   * system (central body, planets, space stations, jump gates — the
+   * discoverable set minus the asteroid clusters) discovered. */
+  isSystemNavComplete() {
+    return isNavComplete(this.discovery, this.systemRecord?.id, this.systemContent);
+  }
+
+  /**
+   * 'Unlock {System} Jumpgates' completed (SYSTEM category): the system's
+   * gates AND the return gates in the systems they jump to go ACTIVE.
+   *
+   * The activation keys are per-run world state (the registry-backed set —
+   * New Game clears, a load restores). The current system's gate entities
+   * wake up here and, per data/gates.json → ACTIVITY, each anchored gate
+   * carries a level-1 tether at its own position (the room to move — in a
+   * barren system, the whole room). The linked systems' return gates flip
+   * their content record now (or on entry — the create() pass); their
+   * entities + tethers materialise when the player arrives (the jump
+   * mechanic, later). Idempotent throughout.
+   */
+  _activateSystemJumpgates(sysId) {
+    const level = Math.max(1, Math.floor(Number(config.get('gates.activation.tetherLevel', 1)) || 1));
+    const keys = activationKeys(this.galaxy, sysId);
+    for (const k of keys) this.activatedGates.add(k);
+
+    // Current system — the gate entities wake + anchor their tethers.
+    for (const gt of this.systemGates ?? []) {
+      if (!gt.gate) continue;
+      if (!this.activatedGates.has(`${sysId}>${gt.gate.to}`)) continue;
+      gt.activate();
+      this.tetherField.add(`gate:${gt.gate.id}`, gt.x, gt.y, level, gt.gate.name ?? '');
+    }
+
+    // Linked systems — flip the cached content (ungenerated systems flip
+    // in the create() pass on entry; both paths are idempotent).
+    for (const [sid, content] of this.galaxy.contentCache) applyActivation(content, sid, this.activatedGates);
+
+    this.consoleToast(`JUMP GATES ONLINE — ${String(this.systemRecord?.name ?? sysId).toUpperCase()}`, {
+      glyph: '⌁',
+      glyphColor: toCss(themeColor('neon', 0x00e5ff)),
+    });
+  }
+
   /** The completion ceremony: SFX, toast, the window repaint. */
   _completeResearchFx(catId, id, node) {
     this.playSfx('discovery'); // the 'something new is here' voice (data/sfx.json)
@@ -1778,9 +1894,12 @@ export class GameScene extends Phaser.Scene {
   }
 
   /**
-   * Apply a tech's effects (node.effects, data/research/<cat>.json).
-   *  tether     { level: N } → the home world's tether field strengthens
-   *  capability "flag"     → a scene capability set (future systems read it)
+   * Apply a tech's effects (node.effects, data/research/<cat>.json — or
+   * the SYSTEM category's live tree). Known shapes:
+   *  tether       { level: N } → the home world's tether field strengthens
+   *  capability   "flag"      → a scene capability set (future systems read it)
+   *  activateGates true       → the SYSTEM category: the system's jump gates
+   *                             + the linked systems' return gates go ACTIVE
    * Unknown shapes are logged and skipped — data can lead code a step.
    */
   _applyResearchEffects(effects, node) {
@@ -1797,6 +1916,10 @@ export class GameScene extends Phaser.Scene {
       } else if (type === 'capability' && typeof spec === 'string') {
         this.researchCapabilities = this.researchCapabilities ?? new Set();
         this.researchCapabilities.add(spec);
+      } else if (type === 'activateGates' && spec) {
+        // SYSTEM category — the node id is "<systemId>_gates".
+        const sysId = String(node?.id ?? '').replace(/_gates$/, '');
+        if (sysId) this._activateSystemJumpgates(sysId);
       } else {
         console.warn(`[orbit] research: unknown effect ${type}`, spec, node?.id);
       }
diff --git a/js/ui/ResearchWindow.js b/js/ui/ResearchWindow.js
index b7431f3..0cb57c8 100644
--- a/js/ui/ResearchWindow.js
+++ b/js/ui/ResearchWindow.js
@@ -119,7 +119,10 @@ export class ResearchWindow extends Phaser.GameObjects.Container {
 
   /**
    * @param {Phaser.Scene} scene the owning scene (GameScene)
-   * @param {object} o { state: ResearchState, onResearch(catId, id) }
+   * @param {object} o { state: ResearchState, onResearch(catId, id),
+   *   systemTree?: the DYNAMIC category's live tree (SystemCategory —
+   *   the per-solar-system SYSTEM tree; categories flagged `dynamic` in
+   *   research.json have no data file and are served from this) }
    */
   constructor(scene, o = {}) {
     super(scene, 0, 0);
@@ -129,6 +132,7 @@ export class ResearchWindow extends Phaser.GameObjects.Container {
     this.setDepth(80); // above save panel (70), sub-bar (60), deck (50)
 
     this.state = o.state ?? null;
+    this.systemTree = o.systemTree ?? null; // the dynamic category's live tree
     this.onResearch = typeof o.onResearch === 'function' ? o.onResearch : null;
 
     this.openState = 'closed'; // closed | opening | open | closing
@@ -138,6 +142,7 @@ export class ResearchWindow extends Phaser.GameObjects.Container {
     this.selected = null; // { category, id }
     this.lastSelected = new Map();
     this.activeCat = null;
+    this._lastSelSt = null; // the selected node's last painted state (live repaint)
     this.glitch = { until: 0, next: 0, level: 0.8 };
     this.sweep = { t0: 0, next: 0 };
     this._lastPct = undefined;
@@ -588,6 +593,13 @@ export class ResearchWindow extends Phaser.GameObjects.Container {
   }
 
   // ── right: the tech trees ─────────────────────────────────────────────────
+  /** A category's tree: the DYNAMIC one (SystemCategory) is the scene's
+   * live per-system tree — no data file; the rest read data/research/<id>.json. */
+  _treeFor(catId) {
+    if (this.systemTree && catId === this.systemTree.id) return this.systemTree;
+    return loadCategory(catId);
+  }
+
   _buildTrees() {
     const { rightX, treeTop, treeH, rightW } = this.geo;
     this.trees = new Map();
@@ -601,7 +613,7 @@ export class ResearchWindow extends Phaser.GameObjects.Container {
       letterSpacing: 1.5,
     });
     for (const cat of categories()) {
-      const tree = loadCategory(cat.id);
+      const tree = this._treeFor(cat.id);
       if (!tree) continue;
       for (const id of tree.order) {
         probe.setText(String(tree.nodes[id].label ?? id).toUpperCase());
@@ -613,7 +625,7 @@ export class ResearchWindow extends Phaser.GameObjects.Container {
     const nodeH = 48;
 
     for (const cat of categories()) {
-      const tree = loadCategory(cat.id);
+      const tree = this._treeFor(cat.id);
       if (!tree) continue;
       const layout = layoutTree(tree);
       const rows = layout.rows;
@@ -936,6 +948,7 @@ export class ResearchWindow extends Phaser.GameObjects.Container {
     const state = this.state;
     const accent = toColor(entry.tree.accent, C.neon);
     const st = this._nodeState(node.id);
+    node.__st = st; // update() repaints on state flips (the chart completes, a run starts)
     const w = node.w;
     const h = node.h;
     const g = node.g;
@@ -1123,6 +1136,7 @@ export class ResearchWindow extends Phaser.GameObjects.Container {
     for (const [catId, t] of this.trees) t.cont.setVisible(catId === category);
     this._paintAll(category);
     this._paintDetail(true);
+    this._lastSelSt = this._nodeState(id);
   }
 
   switchCategory(catId) {
@@ -1135,10 +1149,12 @@ export class ResearchWindow extends Phaser.GameObjects.Container {
       this.selected = { category: catId, id: last };
       this._paintAll(catId);
       this._paintDetail(true);
+      this._lastSelSt = this._nodeState(last);
     } else {
       this.selected = null;
       this._paintAll(catId);
       this._paintDetail(false);
+      this._lastSelSt = null;
     }
   }
 
@@ -1198,6 +1214,10 @@ export class ResearchWindow extends Phaser.GameObjects.Container {
     const missingStr = missing
       .map((m) => String(entry.tree.nodes[m]?.label ?? m).toUpperCase())
       .join(' + ');
+    // A tree may explain a gated node (SystemCategory's chart-completion
+    // gate: requires are all met, but the system isn't fully charted yet).
+    const lockNote =
+      typeof entry.tree.lockNote === 'function' ? entry.tree.lockNote(state, sel.id) : null;
     let meta;
     let metaColor;
     if (active && active.id === sel.id && active.category === sel.category) {
@@ -1209,6 +1229,9 @@ export class ResearchWindow extends Phaser.GameObjects.Container {
     } else if (missing.length) {
       meta = `LOCKED · REQUIRES ${missingStr}`;
       metaColor = C.amber;
+    } else if (lockNote) {
+      meta = `LOCKED · ${lockNote}`;
+      metaColor = C.amber;
     } else {
       meta = `AVAILABLE · DURATION ${durStr}`;
       metaColor = accent;
@@ -1284,6 +1307,7 @@ export class ResearchWindow extends Phaser.GameObjects.Container {
     if (!this.activeCat) return;
     this._paintAll(this.activeCat);
     this._paintDetail(false);
+    this._lastSelSt = this.selected ? this._nodeState(this.selected.id) : null;
     this._paintStatusStrip();
   }
 
@@ -1473,12 +1497,23 @@ export class ResearchWindow extends Phaser.GameObjects.Container {
     const entry = this.activeCat ? this.trees.get(this.activeCat) : null;
     if (entry && !this.reveal.length) {
       for (const node of entry.nodes.values()) {
-        if (this._nodeState(node.id) === 'available') {
+        const st = this._nodeState(node.id);
+        if (st !== node.__st) this._paintNode(node); // state flipped live (a chart completes under the open console…)
+        if (st === 'available') {
           node.cont.setAlpha(0.88 + 0.12 * Math.sin(time * 0.0035 + node.cont.x * 0.01));
         } else {
           node.cont.setAlpha(1);
         }
       }
+      // …and the detail readout follows the selected node's flips (its
+      // button turns LOCKED → RESEARCH as the system's chart completes).
+      if (this.selected && this.selected.category === entry.tree.id) {
+        const st = this._nodeState(this.selected.id);
+        if (st !== this._lastSelSt) {
+          this._lastSelSt = st;
+          this._paintDetail(false);
+        }
+      }
       // energy pulses down the powered edges
       const pg = entry.pulseG;
       pg.clear();