diff --git a/package-lock.json b/package-lock.json
index 9d042ac..f1be53e 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -9,7 +9,6 @@
       "version": "0.1.0",
       "license": "MIT",
       "dependencies": {
-        "chess.js": "^1.1.2",
         "express": "^4.18.2",
         "socket.io": "^4.7.2",
         "uuid": "^9.0.0"
@@ -129,12 +128,6 @@
         "url": "https://github.com/sponsors/ljharb"
       }
     },
-    "node_modules/chess.js": {
-      "version": "1.4.0",
-      "resolved": "https://registry.npmjs.org/chess.js/-/chess.js-1.4.0.tgz",
-      "integrity": "sha512-BBJgrrtKQOzFLonR0l+k64A98NLemPwNsCskwb+29bRwobUa4iTm51E1kwGPbWXAcfdDa18nad6vpPPKPWarqw==",
-      "license": "BSD-2-Clause"
-    },
     "node_modules/content-disposition": {
       "version": "0.5.4",
       "resolved": "https://registry.npmjs.org/content-disposition/-/content-disposition-0.5.4.tgz",
diff --git a/package.json b/package.json
index d20ea26..844fbaf 100644
--- a/package.json
+++ b/package.json
@@ -11,7 +11,6 @@
   "author": "Didictateur",
   "license": "MIT",
   "dependencies": {
-    "chess.js": "^1.1.2",
     "express": "^4.18.2",
     "socket.io": "^4.7.2",
     "uuid": "^9.0.0"
diff --git a/public/game.html b/public/game.html
index 34e7007..965edfc 100644
--- a/public/game.html
+++ b/public/game.html
@@ -111,7 +111,28 @@
 
     connectAndJoin();
 
-    // allow clicking on the board to request legal moves for a square
+    // show markers for legal moves when clicking any square (any piece color)
+    function clearLegalMarkers(){
+      const prev = boardEl.querySelectorAll('.move-marker');
+      prev.forEach(p=>p.remove());
+    }
+
+    function showLegalMoves(moves){
+      clearLegalMarkers();
+      (moves||[]).forEach(m => {
+        const to = m.to || (m.move && m.move.to);
+        if(!to) return;
+        const target = boardEl.querySelector(`.square[data-square="${to}"]`);
+        if(!target) return;
+        const marker = document.createElement('div');
+        marker.className = 'move-marker';
+        // store metadata if needed later
+        marker.dataset.from = m.from || '';
+        marker.dataset.to = to;
+        target.appendChild(marker);
+      });
+    }
+
     if(boardEl){
       boardEl.addEventListener('click', (ev)=>{
         const sqEl = ev.target.closest && ev.target.closest('.square');
@@ -120,8 +141,9 @@
         if(!square) return;
         if(socket){
           socket.emit('game:legalMoves', { roomId, square }, (resp)=>{
-            if(resp && resp.error){ log('legalMoves error', resp); return; }
+            if(resp && resp.error){ log('legalMoves error', resp); clearLegalMarkers(); return; }
             log('legalMoves for', square, resp.moves || resp);
+            showLegalMoves(resp.moves || []);
           });
         }
       });
diff --git a/public/styles/style.css b/public/styles/style.css
index 40f32ae..3ae6f1e 100644
--- a/public/styles/style.css
+++ b/public/styles/style.css
@@ -47,6 +47,15 @@ a:hover{text-decoration:underline}
 .square{width:100%;height:100%;display:flex;align-items:center;justify-content:center}
 .square img, .piece{max-width:78%;max-height:78%;user-select:none}
 
+/* marker shown on target squares for legal moves */
+.square{position:relative}
+.square .move-marker{
+  position:absolute;
+  left:50%;top:50%;transform:translate(-50%,-50%);
+  width:18%;height:18%;border-radius:50%;pointer-events:none;background:rgba(96,165,250,0.95);
+  box-shadow:0 2px 6px rgba(2,6,23,0.6);z-index:3
+}
+
 /* basic checkerboard coloring */
 .square.light{background: linear-gradient(180deg, rgba(255,255,255,0.02), rgba(255,255,255,0.01));}
 .square.dark{background: linear-gradient(180deg, rgba(0,0,0,0.18), rgba(0,0,0,0.12));}
diff --git a/server.js b/server.js
index f504a0c..f4e9a50 100644
--- a/server.js
+++ b/server.js
@@ -1,7 +1,6 @@
 const express = require('express');
 const http = require('http');
 const { Server } = require('socket.io');
-const { Chess } = require('chess.js');
 const { v4: uuidv4 } = require('uuid');
 
 const app = express();
@@ -15,24 +14,36 @@ app.use(express.static('public'));
 app.use('/assets', express.static(path.join(__dirname, 'assets')));
 
 // In-memory rooms store. For production replace with persistent store.
-// room = { id, chess: Chess, players: [{id, socketId, color}], status }
+// room = { id, boardFEN: string|null, turn: 'w'|'b'|null, players: [{id, socketId, color}], status }
 const rooms = new Map();
 
+// Placeholder: compute legal moves for a square in the given room.
+// This is intentionally a stub — you will implement the full rules engine.
+// (fields like { from, to, piece, color, flags, captured, san } are typical).
+function computeLegalMoves(room, square){
+  // TODO: implement rule engine. For now return empty array so client shows nothing.
+  return [];
+}
+
 app.post('/rooms', (req, res) => {
   const id = uuidv4().slice(0, 8);
   // allow optional board size in request body (default 8)
   const size = (req.body && parseInt(req.body.size, 10)) || 8;
-  // For standard 8x8 chess we use chess.js. For other sizes we keep a placeholder state
-  const chess = size === 8 ? new Chess() : null;
+  // For standard 8x8 we initialize a FEN string as the canonical board state.
+  // manually (or by a separate engine). This server stores the board FEN and
+  // the active turn so custom logic can operate on them.
+  const startingFEN = 'rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1';
+  const boardFEN = size === 8 ? startingFEN : null;
+  const turn = size === 8 ? 'w' : null; // 'w' or 'b'
   // hostId will be set when the first player joins
-  rooms.set(id, { id, chess, players: [], status: 'waiting', hostId: null, size, cards: {}, playedCards: [], removalTimers: new Map() });
+  rooms.set(id, { id, boardFEN, turn, players: [], status: 'waiting', hostId: null, size, cards: {}, playedCards: [], removalTimers: new Map() });
   res.json({ roomId: id, size });
 });
 
 app.get('/rooms/:id', (req, res) => {
   const room = rooms.get(req.params.id);
   if (!room) return res.status(404).json({ error: 'room not found' });
-  const fen = room.chess ? room.chess.fen() : null;
+  const fen = room.boardFEN || null;
   res.json({ id: room.id, fen, size: room.size, players: room.players.map(p => ({ id: p.id, color: p.color })), status: room.status, hostId: room.hostId, cards: Object.keys(room.cards || {}) });
 });
 
@@ -70,7 +81,7 @@ io.on('connection', (socket) => {
 
 
     io.to(roomId).emit('room:update', {
-      fen: room.chess ? room.chess.fen() : null,
+      fen: room.boardFEN || null,
       players: room.players.map(p => ({ id: p.id, color: p.color })),
       status: room.status,
       hostId: room.hostId,
@@ -85,26 +96,10 @@ io.on('connection', (socket) => {
     const room = rooms.get(roomId);
     if (!room) return cb && cb({ error: 'room not found' });
 
-    const chess = room.chess;
-
-    // If we have a chess.js instance (standard 8x8) use it for validation
-    if (!chess) return cb && cb({ error: 'custom board sizes not yet supported for moves' });
-
-    // Validate move
-    const move = chess.move({ from, to, promotion });
-    if (!move) return cb && cb({ error: 'invalid move' });
-
-    io.to(roomId).emit('move:moved', { move, fen: chess.fen() });
-
-    if (chess.isGameOver()) {
-      room.status = 'finished';
-      let result = 'draw';
-      if (chess.isCheckmate()) result = 'checkmate';
-      else if (chess.isStalemate()) result = 'stalemate';
-      io.to(roomId).emit('game:over', { result, fen: chess.fen() });
-    }
-
-    cb && cb({ ok: true, move, fen: chess.fen() });
+    // Move handling/validation is intentionally not implemented here because
+    // Implement a function to validate & apply moves on the room state and
+    // then emit 'move:moved' with move details and updated room.boardFEN.
+    return cb && cb({ error: 'move handling not implemented on server; implement custom engine' });
   });
 
   // Host can start the game explicitly
@@ -120,9 +115,9 @@ io.on('connection', (socket) => {
     if (!room.hostId || room.hostId !== senderId) return cb && cb({ error: 'only host can start' });
 
     room.status = 'playing';
-    io.to(roomId).emit('game:started', { roomId, fen: room.chess.fen() });
+    io.to(roomId).emit('game:started', { roomId, fen: room.boardFEN });
     io.to(roomId).emit('room:update', {
-      fen: room.chess ? room.chess.fen() : null,
+      fen: room.boardFEN || null,
       players: room.players.map(p => ({ id: p.id, color: p.color })),
       status: room.status,
       hostId: room.hostId,
@@ -149,7 +144,7 @@ io.on('connection', (socket) => {
         }
         if (room.players.length < 2 && room.status === 'playing') room.status = 'waiting';
         io.to(roomId).emit('room:update', {
-          fen: room.chess ? room.chess.fen() : null,
+          fen: room.boardFEN || null,
           players: room.players.map(p => ({ id: p.id, color: p.color })),
           status: room.status,
           hostId: room.hostId,
@@ -167,7 +162,7 @@ io.on('connection', (socket) => {
         room.hostId = room.players[0] ? room.players[0].id : null;
       }
       io.to(roomId).emit('room:update', {
-        fen: room.chess ? room.chess.fen() : null,
+        fen: room.boardFEN || null,
         players: room.players.map(p => ({ id: p.id, color: p.color })),
         status: room.status,
         hostId: room.hostId,
@@ -177,15 +172,15 @@ io.on('connection', (socket) => {
     }
   });
 
-  // Provide legal moves for a given square (for standard 8x8 via chess.js)
+  // delegates to `computeLegalMoves` which is a stub you should implement.
   socket.on('game:legalMoves', ({ roomId, square }, cb) => {
     const room = rooms.get(roomId);
     if (!room) return cb && cb({ error: 'room not found' });
-    if (!room.chess) return cb && cb({ error: 'legal moves not supported for custom board sizes yet', moves: [] });
     try{
-      const moves = room.chess.moves({ square, verbose: true }) || [];
+      const moves = computeLegalMoves(room, square) || [];
       return cb && cb({ ok: true, moves });
     }catch(e){
+      console.error('game:legalMoves error', e);
       return cb && cb({ error: 'invalid square', moves: [] });
     }
   });