feedback6 R21A: a 突袭 member may land on a teammate's half when both halves of the field are taken — the two-helper 联防 field and the Final Assault / Hidden Core pair field (the owner's decision of 2026-10-07): Battle.onFieldBoard (onOwnBoard of any player of the battle) read by raidTile only; a lone 联防 helper's empty half, a solo boss field's other half and the hand / 临时整备区 rows stay closed, every other landing rule kept, 乌尔比安's S3 【移动】 keeps onOwnBoard; golden: 8 moved, each parting from the parent at a member's first landing on its teammate's half (checked tick by tick with the parent instrumented) — fields boss-boss_2 / 3 / 4 / 5 / 6-pair and hidden-boss_8 / 10-pair (the right player's 缄默德克萨斯 / 伊内丝 / 仇白 / 耀骑士临光 on the left player's half, 1–7 landings per battle, the first 0.3–39.8 s in), matches coop4-ABYSS-7 (round 6's two-helper 联防: ai_2's 斯卡蒂 on ai_1's half at 52 s; only ai_1 / ai_2 dmgDealt move, 8263 between them); unite-2 unchanged (its two landings stay on their own half)

Tests: test/sim/feedback5-raid-own-board.test.js — the pair field (the right player's member onto the left telin's board tile (2,3), the left player's onto the mirrored right (2,17), the hand rows closed) and the two-helper 联防 (each helper onto the other's half; 乌尔比安 beside a teammate stays on his own) fail on the parent; the solo boss field's hand rows and the lone helper unchanged.
Docs: docs/history/0.2.1.md (new, §26; §26.1 cites the owner's decision and PRTS 卫戍协议/帮助 §联防阶段), the DESIGN index row and versions line, a pointer from §25.18.1, docs/SIM.md (onFieldBoard; onOwnBoard now 乌尔比安's only).

server/sim/battle/players.js

@@ -78,9 +78,9 @@ export class BattlePlayers {
    * Whether field tile (r, c) lies on player `ps`'s own board: the board region GEO.FIELD (rows 9–12, cols 2–10, the
    * tiles its pieces are deployed on) mapped onto this field — the 联防 right-hand helper's +8 columns, the boss field's
    * rows 2–5, the mirrored right half of a pair (whatever coordinates the player's input uses). Never the hand / 临时
-   * 整备区 rows of a boss field (rows 0–1, inside BOSS_RECT) nor the other half of a 联防 or boss field. Automatic
-   * redeployments and moves that must stay where the player could deploy read it (the 突袭 landing, bonds/addon/battle.js
-   * raidTile; 乌尔比安's S3 【移动】, kits/ops/chess_char_5_05-ulpia.js).
+   * 整备区 rows of a boss field (rows 0–1, inside BOSS_RECT) nor the other half of a 联防 or boss field. Moves that must
+   * stay where the player could deploy read it (乌尔比安's S3 【移动】, kits/ops/chess_char_5_05-ulpia.js); the 突袭
+   * landing reads onFieldBoard (any player of this field).
    */
   onOwnBoard(ps, r, c) {
     if (!ps) return false;
@@ -94,6 +94,18 @@ export class BattlePlayers {
     return keys.has(r * COLS + c);
   }
 
+  /**
+   * Whether field tile (r, c) lies on the board of a player standing on this field: onOwnBoard of one of `players`,
+   * the players whose units this battle holds (a teammate eliminated before it or playing another field is not one).
+   * Both halves on the two-helper 联防 field and on a Final Assault / Hidden Core pair field; the own half only for a
+   * lone 联防 helper and on a solo boss field; never a boss field's hand / 临时整备区 rows. The 突袭 landing reads it
+   * (bonds/addon/battle.js raidTile — the owner's decision of 2026-10-07, DESIGN §26.1).
+   */
+  onFieldBoard(r, c) {
+    for (const ps of this.players) if (this.onOwnBoard(ps, r, c)) return true;
+    return false;
+  }
+
   _boardTile(ps, row, col) {
     const bossLike = this.kind === 'boss' || this.kind === 'hidden';
     let r = row;