diff --git a/packages/backend/src/core/MahjongService.ts b/packages/backend/src/core/MahjongService.ts
index c71e18fb85..27a3c5c495 100644
--- a/packages/backend/src/core/MahjongService.ts
+++ b/packages/backend/src/core/MahjongService.ts
@@ -519,14 +519,9 @@ export class MahjongService implements OnApplicationShutdown, OnModuleInit {
 		const engine = new Mahjong.MasterGameEngine(room.gameState);
 		const myHouse = getHouseOfUserId(room, engine, user.id);
 
-		if (riichi) {
-			if (Mahjong.Utils.getHoraTiles(engine.state.handTiles[myHouse]).length === 0) return;
-			if (engine.state.points[myHouse] < 1000) return;
-		}
-
 		await this.clearTurnWaitingTimer(room.id);
 
-		await this.dahai(room, engine, myHouse, tile);
+		await this.dahai(room, engine, myHouse, tile, riichi);
 	}
 
 	@bindThis
diff --git a/packages/misskey-mahjong/src/engine.master.ts b/packages/misskey-mahjong/src/engine.master.ts
index 20df90bac8..6a3bd45ca4 100644
--- a/packages/misskey-mahjong/src/engine.master.ts
+++ b/packages/misskey-mahjong/src/engine.master.ts
@@ -238,6 +238,11 @@ export class MasterGameEngine {
 	public commit_dahai(house: House, tile: Tile, riichi = false) {
 		if (this.state.turn !== house) throw new Error('Not your turn');
 
+		if (riichi) {
+			if (Utils.getHoraTiles(this.state.handTiles[house]).length === 0) throw new Error('Not tenpai');
+			if (this.state.points[house] < 1000) throw new Error('Not enough points');
+		}
+
 		const handTiles = this.state.handTiles[house];
 		if (!handTiles.includes(tile)) throw new Error('No such tile in your hand');
 		handTiles.splice(handTiles.indexOf(tile), 1);