const canvas = document.getElementById('canvas'); const ctx = canvas.getContext('2d'); let board = [ ['', '', '', ''], ['', '', '', ''], ['', '', '', ''], ['', '', '', ''] ]; let turn = 'white'; let selectedPiece = null; let gameEnded = false; function drawBoard() { ctx.clearRect(0, 0, canvas.width, canvas.height); ctx.fillStyle = '#f0d9b5'; ctx.fillRect(0, 0, canvas.width, canvas.height); for (let i = 0; i < 4; i++) { for (let j = 0; j < 4; j++) { if ((i + j) % 2 === 0) { ctx.fillStyle = '#b58863'; } else { ctx.fillStyle = '#f0d9b5'; } ctx.fillRect(j * 50, i * 50, 50, 50); if (board[i][j] !== '') { ctx.font = '30px Arial'; if (board[i][j].charAt(0) === 'w') { ctx.fillStyle = '#fff'; } else { ctx.fillStyle = '#000'; } ctx.fillText(board[i][j].charAt(1), j * 50 + 20, i * 50 + 35); } } } } function selectPiece(x, y) { if (board[y][x] !== '' && board[y][x].charAt(0) === turn.charAt(0)) { selectedPiece = {x, y}; } } function movePiece(x, y) { if (selectedPiece !== null && board[y][x].charAt(0) !== turn.charAt(0)) { if (isValidMove(selectedPiece.x, selectedPiece.y, x, y)) { board[y][x] = board[selectedPiece.y][selectedPiece.x]; board[selectedPiece.y][selectedPiece.x] = ''; selectedPiece = null; turn = turn === 'white' ? 'black' : 'white'; } } } function isValidMove(startX, startY, endX, endY) { if (board[startY][startX].charAt(1) === 'P') { if (board[startY][startX].charAt(0) === 'w') { if (endY === startY - 1 && endX === startX && board[endY][endX] === '') { return true; } else if (endY === startY - 2 && endX === startX && board[endY][endX] === '' && board[startY - 1][startX] === '') { return true; } else if (endY === startY - 1 && Math.abs(endX - startX) === 1 && board[endY][endX].charAt(0) === 'b') { return true; } } else { if (endY === startY + 1 && endX === startX && board[endY][endX] === '') { return true; } else if (endY === startY + 2 && endX === startX && board[endY][endX] === '' && board[startY + 1][startX] === '') { return true; } else if (endY === startY + 1 && Math.abs(endX - startX) === 1 && board[endY][endX].charAt(0) === 'w') { return true; } } } else if (board[startY][startX].charAt(1) === 'R') { if (startX === endX || startY === endY) { if (startX === endX) { let min = Math.min(startY, endY); let max = Math.max(startY, endY); for (let i = min + 1; i < max; i++) { if (board[i][startX] !== '') { return false; } } return true; } else { let min = Math.min(startX, endX); let max = Math.max(startX, endX); for (let i = min + 1; i < max; i++) { if (board[startY][i] !== '') { return false; } } return true; } } } else if (board[startY][startX].charAt(1) === 'N') { if ((Math.abs(endX - startX) === 1 && Math.abs(endY - startY) === 2) || (Math.abs(endX - startX) === 2 && Math.abs(endY - startY) === 1)) { return true; } } else if (board[startY][startX].charAt(1) === 'B') { if (Math.abs(endX - startX) === Math.abs(endY - startY)) { let xDir = endX > startX ? 1 : -1; let yDir = endY > startY ? 1 : -1; let x = startX + xDir; let y = startY + yDir; while (x !== endX && y !== endY) { if (board[y][x] !== '') { return false; } x += xDir; y += yDir; } return true; } } else if (board[startY][startX].charAt(1) === 'Q') { if (startX === endX || startY === endY) { if (startX === endX) { let min = Math.min(startY, endY); let max = Math.max(startY, endY); for (let i = min + 1; i < max; i++) { if (board[i][startX] !== '') { return false; } } return true; } else { let min = Math.min(startX, endX); let max = Math.max(startX, endX); for (let i = min + 1; i < max; i++) { if (board[startY][i] !== '') { return false; } } return true; } } else if (Math.abs(endX - startX) === Math.abs(endY - startY)) { let xDir = endX > startX ? 1 : -1; let yDir = endY > startY ? 1 : -1; let x = startX + xDir; let y = startY + yDir; while (x !== endX && y !== endY) { if (board[y][x] !== '') { return false; } x += xDir; y += yDir; } return true; } } else if (board[startY][startX].charAt(1) === 'K') { if (Math.abs(endX - startX) <= 1 && Math.abs(endY - startY) <= 1) { return true; } } return false; } function checkEndGame() { let whiteKing = false; let blackKing = false; for (let i = 0; i < 4; i++) { for (let j = 0; j < 4; j++) { if (board[i][j].charAt(1) === 'K') { if (board[i][j].charAt(0) === 'w') { whiteKing = true; } else { blackKing = true; } } } } if (!whiteKing) { alert('Black wins!'); gameEnded = true; } else if (!blackKing) { alert('White wins!'); gameEnded = true; } } drawBoard(); document.addEventListener('keydown', event => { if (!gameEnded) { if (event.keyCode === 37) { if (selectedPiece !== null && selectedPiece.x > 0) { selectedPiece.x--; drawBoard(); } } else if (event.keyCode === 38) { if (selectedPiece !== null && selectedPiece.y > 0) { selectedPiece.y--; drawBoard(); } } else if (event.keyCode === 39) { if (selectedPiece !== null && selectedPiece.x < 3) { selectedPiece.x++; drawBoard(); } } else if (event.keyCode === 40) { if (selectedPiece !== null && selectedPiece.y < 3) { selectedPiece.y++; drawBoard(); } } else if (event.keyCode === 13) { if (selectedPiece === null) { selectPiece(Math.floor(Math.random() * 4), Math.floor(Math.random() * 4)); drawBoard(); } else { movePiece(selectedPiece.x, selectedPiece.y); checkEndGame(); drawBoard(); } } } });

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Micro Chess: Play quick games of chess on a small 4x4 board. Ideal for quick strategic thinking sessions.

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