diff --git a/docs/development/current/main/phases/phase-29ap/P7-PATTERN9-LEGACY-REMOVAL-DECISION-INSTRUCTIONS.md b/docs/development/current/main/phases/phase-29ap/P7-PATTERN9-LEGACY-REMOVAL-DECISION-INSTRUCTIONS.md
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@@ -0,0 +1,73 @@
+---
+Status: Ready
+Scope: docs+verification (Pattern9 legacy table removal decision)
+Related:
+  - docs/development/current/main/phases/phase-29ap/README.md
+  - docs/development/current/main/design/coreplan-migration-roadmap-ssot.md
+  - docs/development/current/main/phases/phase-29ae/README.md
+  - tools/smokes/v2/profiles/integration/joinir/phase29ae_regression_pack_vm.sh
+  - src/mir/builder/control_flow/joinir/patterns/router.rs
+---
+
+# Phase 29ap P7: Pattern9 legacy table removal decision (and removal if safe)
+
+Date: 2025-12-31  
+Status: Ready for execution  
+Goal: Pattern9 を JoinIR legacy table から外しても SSOT gate が壊れないかを確認し、OKなら撤去する。
+
+## 非目的
+
+- Pattern9 の新規実装/拡張
+- 既定挙動・恒常ログの変更
+- 新しい env var 追加
+
+## Step 0: P6 の着地確認 (必須)
+
+- `git status -sb` が clean
+- Gate が緑:
+  - `./tools/smokes/v2/run.sh --profile quick`
+  - `./tools/smokes/v2/profiles/integration/joinir/phase29ae_regression_pack_vm.sh`
+
+## Step 1: Pattern9 使用状況の監査 (撤去可否の判断材料)
+
+列挙して「stdlib/quick/gate が依存しているか」を確認する:
+
+- 参照箇所:
+  - `rg -n "Pattern9|pattern9|AccumConstLoop" src/ apps/ tools/ docs/`
+- legacy table への掲載有無:
+  - `rg -n "legacy.*Pattern9|Pattern9" src/mir/builder/control_flow/joinir/patterns/router.rs`
+- smoke/gate の対象:
+  - `rg -n "pattern9" tools/smokes/v2/profiles/integration/joinir/phase29ae_regression_pack_vm.sh tools/smokes/v2/profiles/integration/joinir/* || true`
+
+判断基準 (SSOT):
+
+- stdlib / quick / gate が Pattern9 依存 → P7 は「撤去保留」として理由を docs に固定
+- 上記に該当しない → 撤去 OK
+
+## Step 2A: 撤去 OK の場合
+
+- `src/mir/builder/control_flow/joinir/patterns/router.rs` から Pattern9 entry を削除
+- Pattern9 wrapper/module が未使用なら削除 or plan への委譲に縮退
+- legacy pack があれば「legacy扱い」の注記だけ残す (gate には入れない)
+
+## Step 2B: 撤去 NG の場合
+
+- `docs/development/current/main/phases/phase-29ap/README.md` に保留理由を 1 段落で固定
+- `docs/development/current/main/design/coreplan-migration-roadmap-ssot.md` の Next を P8 に進める
+
+## Step 3: 検証 (必須)
+
+- `cargo build --release`
+- `./tools/smokes/v2/run.sh --profile quick`
+- `./tools/smokes/v2/profiles/integration/joinir/phase29ae_regression_pack_vm.sh`
+
+## Step 4: docs 更新 (最小)
+
+- `docs/development/current/main/phases/phase-29ap/README.md` に P7 結果を反映
+- `docs/development/current/main/10-Now.md`
+- `docs/development/current/main/30-Backlog.md`
+- `docs/development/current/main/design/coreplan-migration-roadmap-ssot.md`
+
+## コミット
+
+- `git commit -m "phase29ap(p7): decide pattern9 legacy removal"`
diff --git a/docs/development/current/main/phases/phase-29ap/README.md b/docs/development/current/main/phases/phase-29ap/README.md
index a2b0ad45..bcb34be2 100644
--- a/docs/development/current/main/phases/phase-29ap/README.md
+++ b/docs/development/current/main/phases/phase-29ap/README.md
@@ -83,4 +83,5 @@ Gate (SSOT):
 
 ## Next (planned)
 
-- P7: Legacy table shrink (Pattern9 removal) or leave as-is with justification
+- P7: Pattern9 legacy table removal decision
+  - `docs/development/current/main/phases/phase-29ap/P7-PATTERN9-LEGACY-REMOVAL-DECISION-INSTRUCTIONS.md`