diff --git a/packages/backend/src/server/api/endpoint-list.ts b/packages/backend/src/server/api/endpoint-list.ts
index 34aaef3cc7..531326f3fd 100644
--- a/packages/backend/src/server/api/endpoint-list.ts
+++ b/packages/backend/src/server/api/endpoint-list.ts
@@ -288,6 +288,12 @@ export * as 'invite/create' from './endpoints/invite/create.js';
 export * as 'invite/delete' from './endpoints/invite/delete.js';
 export * as 'invite/limit' from './endpoints/invite/limit.js';
 export * as 'invite/list' from './endpoints/invite/list.js';
+export * as 'mahjong/cancel-match' from './endpoints/mahjong/cancel-match.js';
+export * as 'mahjong/create-room' from './endpoints/mahjong/create-room.js';
+export * as 'mahjong/games' from './endpoints/mahjong/games.js';
+export * as 'mahjong/join-room' from './endpoints/mahjong/join-room.js';
+export * as 'mahjong/show-room' from './endpoints/mahjong/show-room.js';
+export * as 'mahjong/verify' from './endpoints/mahjong/verify.js';
 export * as 'meta' from './endpoints/meta.js';
 export * as 'miauth/gen-token' from './endpoints/miauth/gen-token.js';
 export * as 'mute/create' from './endpoints/mute/create.js';
diff --git a/packages/frontend/src/pages/mahjong/index.vue b/packages/frontend/src/pages/mahjong/index.vue
index 6ca938f73a..a83bb1ec31 100644
--- a/packages/frontend/src/pages/mahjong/index.vue
+++ b/packages/frontend/src/pages/mahjong/index.vue
@@ -24,18 +24,18 @@ SPDX-License-Identifier: AGPL-3.0-only
 <script lang="ts" setup>
 import { computed, onDeactivated, onMounted, onUnmounted, ref } from 'vue';
 import * as Misskey from 'misskey-js';
-import { misskeyApi } from '@/scripts/misskey-api.js';
-import { definePageMetadata } from '@/scripts/page-metadata.js';
+import { useInterval } from '@@/js/use-interval.js';
+import { misskeyApi } from '@/utility/misskey-api.js';
+import { definePage } from '@/page.js';
 import { useStream } from '@/stream.js';
 import MkButton from '@/components/MkButton.vue';
 import MkFolder from '@/components/MkFolder.vue';
 import { i18n } from '@/i18n.js';
-import { $i } from '@/account.js';
+import { $i } from '@/i.js';
 import MkPagination from '@/components/MkPagination.vue';
-import { useRouter } from '@/router/supplier.js';
+import { useRouter } from '@/router.js';
 import * as os from '@/os.js';
-import { useInterval } from '@/scripts/use-interval.js';
-import * as sound from '@/scripts/sound.js';
+import * as sound from '@/utility/sound.js';
 
 const myGamesPagination = {
 	endpoint: 'mahjong/games' as const,
@@ -74,7 +74,7 @@ async function createRoom(ev: MouseEvent) {
 	router.push(`/mahjong/g/${room.id}`);
 }
 
-definePageMetadata(computed(() => ({
+definePage(computed(() => ({
 	title: i18n.ts._mahjong.mahjong,
 	icon: 'ti ti-device-gamepad',
 })));
diff --git a/packages/frontend/src/pages/mahjong/room.game.vue b/packages/frontend/src/pages/mahjong/room.game.vue
index 0f71d6ce63..61b1280d33 100644
--- a/packages/frontend/src/pages/mahjong/room.game.vue
+++ b/packages/frontend/src/pages/mahjong/room.game.vue
@@ -277,21 +277,21 @@ SPDX-License-Identifier: AGPL-3.0-only
 import { computed, onActivated, onDeactivated, onMounted, onUnmounted, reactive, ref, shallowRef, triggerRef, watch } from 'vue';
 import * as Misskey from 'misskey-js';
 import * as Mmj from 'misskey-mahjong';
+import { useInterval } from '@@/js/use-interval.js';
 import XTile from './tile.vue';
 import XHuro from './huro.vue';
 import XHandTiles from './hand-tiles.vue';
 import MkButton from '@/components/MkButton.vue';
 import MkFolder from '@/components/MkFolder.vue';
 import MkSwitch from '@/components/MkSwitch.vue';
-import { deepClone } from '@/scripts/clone.js';
-import { useInterval } from '@/scripts/use-interval.js';
-import { signinRequired } from '@/account.js';
+import { deepClone } from '@/utility/clone.js';
+import { ensureSignin } from '@/i.js';
 import { i18n } from '@/i18n.js';
-import { misskeyApi } from '@/scripts/misskey-api.js';
+import { misskeyApi } from '@/utility/misskey-api.js';
 import { userPage } from '@/filters/user.js';
-import * as sound from '@/scripts/sound.js';
+import * as sound from '@/utility/sound.js';
 import * as os from '@/os.js';
-import { confetti } from '@/scripts/confetti.js';
+import { confetti } from '@/utility/confetti.js';
 
 //#region syntax suger
 function mj$(tid: Mmj.TileId): Mmj.TileInstance {
@@ -303,7 +303,7 @@ function mj$type(tid: Mmj.TileId): Mmj.TileType {
 }
 //#endregion
 
-const $i = signinRequired();
+const $i = ensureSignin();
 
 const props = defineProps<{
 	room: Misskey.entities.MahjongRoomDetailed;
diff --git a/packages/frontend/src/pages/mahjong/room.setting.vue b/packages/frontend/src/pages/mahjong/room.setting.vue
index 36d2eb0387..63f7d72e65 100644
--- a/packages/frontend/src/pages/mahjong/room.setting.vue
+++ b/packages/frontend/src/pages/mahjong/room.setting.vue
@@ -52,18 +52,18 @@ SPDX-License-Identifier: AGPL-3.0-only
 import { computed, watch, ref, onMounted, shallowRef, onUnmounted } from 'vue';
 import * as Misskey from 'misskey-js';
 import * as Mmj from 'misskey-mahjong';
+import type { MenuItem } from '@/types/menu.js';
 import { i18n } from '@/i18n.js';
-import { signinRequired } from '@/account.js';
-import { deepClone } from '@/scripts/clone.js';
+import { ensureSignin } from '@/i.js';
+import { deepClone } from '@/utility/clone.js';
 import MkButton from '@/components/MkButton.vue';
 import MkRadios from '@/components/MkRadios.vue';
 import MkSwitch from '@/components/MkSwitch.vue';
 import MkFolder from '@/components/MkFolder.vue';
 import * as os from '@/os.js';
-import { MenuItem } from '@/types/menu.js';
-import { useRouter } from '@/router/supplier.js';
+import { useRouter } from '@/router.js';
 
-const $i = signinRequired();
+const $i = ensureSignin();
 
 const router = useRouter();
 
diff --git a/packages/frontend/src/pages/mahjong/room.vue b/packages/frontend/src/pages/mahjong/room.vue
index 5119e25660..16bcda1726 100644
--- a/packages/frontend/src/pages/mahjong/room.vue
+++ b/packages/frontend/src/pages/mahjong/room.vue
@@ -12,18 +12,18 @@ SPDX-License-Identifier: AGPL-3.0-only
 <script lang="ts" setup>
 import { computed, watch, ref, onMounted, shallowRef, onUnmounted } from 'vue';
 import * as Misskey from 'misskey-js';
+import { useInterval } from '@@/js/use-interval.js';
 import RoomSetting from './room.setting.vue';
 import RoomGame from './room.game.vue';
-import { misskeyApi } from '@/scripts/misskey-api.js';
-import { definePageMetadata } from '@/scripts/page-metadata.js';
+import { misskeyApi } from '@/utility/misskey-api.js';
+import { definePage } from '@/page.js';
 import { useStream } from '@/stream.js';
-import { signinRequired } from '@/account.js';
-import { useRouter } from '@/router/supplier.js';
+import { ensureSignin } from '@/i.js';
+import { useRouter } from '@/router.js';
 import * as os from '@/os.js';
 import { i18n } from '@/i18n.js';
-import { useInterval } from '@/scripts/use-interval.js';
 
-const $i = signinRequired();
+const $i = ensureSignin();
 
 const router = useRouter();
 
@@ -106,7 +106,7 @@ onUnmounted(() => {
 	}
 });
 
-definePageMetadata(computed(() => ({
+definePage(computed(() => ({
 	title: i18n.ts._mahjong.mahjong,
 	icon: 'ti ti-device-roompad',
 })));
diff --git a/packages/misskey-mahjong/src/common.yaku.ts b/packages/misskey-mahjong/src/common.yaku.ts
index 5b654ffdb4..675650a58c 100644
--- a/packages/misskey-mahjong/src/common.yaku.ts
+++ b/packages/misskey-mahjong/src/common.yaku.ts
@@ -74,20 +74,28 @@ type YakumanName = typeof YAKUMAN_NAMES[number];
 
 export type YakuName = NormalYakuName | YakumanName;
 
-export type HuroForCalcYaku = {
+type Pon = {
 	type: 'pon';
 	tile: TileType;
-} | {
+};
+
+type Cii = {
 	type: 'cii';
 	tiles: [TileType, TileType, TileType];
-} | {
+};
+
+type Ankan = {
 	type: 'ankan';
 	tile: TileType;
-} | {
+};
+
+type Minkan = {
 	type: 'minkan';
 	tile: TileType;
 };
 
+export type HuroForCalcYaku = Pon | Cii | Ankan | Minkan;
+
 export type EnvForCalcYaku = {
 	/**
 	 * 和了る人の手牌(副露牌は含まず、ツモ、ロン牌は含む)
@@ -604,7 +612,7 @@ new SeatWind('seat-wind-n', 'n'),
 		if (fourMentsuOneJyantou == null) return false;
 
 		const shuntsus = fourMentsuOneJyantou.mentsus.filter(tiles => isShuntu(tiles));
-		shuntsus.push(...state.huros.filter(huro => huro.type == 'cii').map(huro => huro.tiles));
+		shuntsus.push(...state.huros.filter((huro): huro is Cii => huro.type == 'cii').map(huro => huro.tiles));
 
 		if (shuntsus.some(tiles => tiles[0] === 'm1' && tiles[1] === 'm2' && tiles[2] === 'm3')) {
 			if (shuntsus.some(tiles => tiles[0] === 'm4' && tiles[1] === 'm5' && tiles[2] === 'm6')) {
diff --git a/packages/misskey-mahjong/src/engine.master.ts b/packages/misskey-mahjong/src/engine.master.ts
index f27fafd011..10fcde24f4 100644
--- a/packages/misskey-mahjong/src/engine.master.ts
+++ b/packages/misskey-mahjong/src/engine.master.ts
@@ -997,19 +997,19 @@ export class MasterGameEngine {
 	}
 
 	public calcCrc32ForUser1(): number {
-		// TODO
+		throw new Error('TODO');
 	}
 
 	public calcCrc32ForUser2(): number {
-		// TODO
+		throw new Error('TODO');
 	}
 
 	public calcCrc32ForUser3(): number {
-		// TODO
+		throw new Error('TODO');
 	}
 
 	public calcCrc32ForUser4(): number {
-		// TODO
+		throw new Error('TODO');
 	}
 
 	public getState(): MasterState {
@@ -1018,5 +1018,5 @@ export class MasterGameEngine {
 }
 
 function commit_dahai(state: MasterState): MasterState {
-
+	throw new Error('Not implemented');
 }
diff --git a/packages/misskey-mahjong/src/serializer.ts b/packages/misskey-mahjong/src/serializer.ts
index 8c9d14990b..d01935c9de 100644
--- a/packages/misskey-mahjong/src/serializer.ts
+++ b/packages/misskey-mahjong/src/serializer.ts
@@ -5,16 +5,22 @@
 
 import { TileType } from './common.js';
 
+export type Player = 1 | 2 | 3 | 4;
+
+export type Operation = 'dahai';
+
+export type OperationCode = 1;
+
 export type Log = {
 	time: number;
-	player: 1 | 2 | 3 | 4;
-	operation: 'dahai';
-	tile: string;
+	player: Player;
+	operation: Operation;
+	tile: TileType;
 };
 
-export type SerializedLog = number[];
+export type SerializedLog = [number, Player, OperationCode, TileCode];
 
-export const TILE_MAP: Record<TileType, number> = {
+export const TILE_MAP = {
 	'm1': 1,
 	'm2': 2,
 	'm3': 3,
@@ -49,9 +55,11 @@ export const TILE_MAP: Record<TileType, number> = {
 	'haku': 32,
 	'hatsu': 33,
 	'chun': 34,
-};
+} as const;
 
-export function serializeTile(tile: TileType): number {
+export type TileCode = typeof TILE_MAP extends Record<string, infer T> ? T : never;
+
+export function serializeTile(tile: TileType): TileCode {
 	return TILE_MAP[tile];
 }
 
@@ -59,8 +67,8 @@ export function deserializeTile(tile: number): TileType {
 	return Object.keys(TILE_MAP).find(key => TILE_MAP[key as TileType] === tile) as TileType;
 }
 
-export function serializeLogs(logs: Log[]) {
-	const _logs: number[][] = [];
+export function serializeLogs(logs: Log[]): SerializedLog[] {
+	const _logs: SerializedLog[] = [];
 
 	for (let i = 0; i < logs.length; i++) {
 		const log = logs[i];
@@ -79,7 +87,7 @@ export function serializeLogs(logs: Log[]) {
 	return _logs;
 }
 
-export function deserializeLogs(logs: SerializedLog[]) {
+export function deserializeLogs(logs: SerializedLog[]): Log[] {
 	const _logs: Log[] = [];
 
 	let time = 0;
@@ -97,7 +105,7 @@ export function deserializeLogs(logs: SerializedLog[]) {
 					time,
 					player: player,
 					operation: 'dahai',
-					tile: log[3],
+					tile: deserializeTile(log[3]),
 				});
 				break;
 			//case 1: