♞ Chess Guide

What Is Chess?

Chess is the world's most famous strategy game: two armies of sixteen pieces face off on an 8x8 board, and the goal is to trap the enemy king in checkmate. It has been played in recognizably modern form for over five hundred years, and despite computers now playing it far better than any human, it remains endlessly rich - every game branches into positions nobody has ever seen before.

Our version implements the full rules of the game - castling, en passant, promotion, stalemate, everything - with a searching AI engine at four difficulty levels, plus real-time online play against friends through the multiplayer lobby.

The Rules

White moves first, then the players alternate, moving one piece per turn. A piece captures by landing on the square an enemy piece occupies. Each piece moves differently:

• Pawn - moves one square forward (two from its starting square), but captures one square diagonally forward. Pawns never move backwards.
• Knight - moves in an L-shape: two squares in one direction, then one square perpendicular. It is the only piece that jumps over others.
• Bishop - any number of squares diagonally. Each bishop stays on one color for the whole game.
• Rook - any number of squares horizontally or vertically.
• Queen - combines rook and bishop: any number of squares in any straight line. Your most powerful piece.
• King - one square in any direction. The king can never move into a square attacked by the enemy.

Three special moves trip up beginners:

• Castling - once per game, the king moves two squares toward a rook and the rook hops to the other side of the king. Allowed only if neither piece has moved, the squares between them are empty, and the king is not in check or passing through an attacked square. It tucks your king into safety and activates a rook in one move.
• En passant - if an enemy pawn advances two squares and lands directly beside your pawn, you may capture it as if it had moved only one square - but only on the very next move.
• Promotion - a pawn that reaches the far end of the board must become a queen, rook, bishop, or knight (almost always a queen).

Check means your king is attacked - you must escape it immediately by moving the king, blocking, or capturing the attacker. Checkmate means there is no escape, and the game ends. Stalemate is different: the player to move has no legal moves but is not in check - that's a draw, not a win, which is why a huge material advantage can still slip away.

Opening Principles

Fight for the center

The four central squares (d4, d5, e4, e5) are the high ground of the board: pieces placed there or controlling them reach more squares and switch between attack and defense faster. Start with a central pawn move like e4 or d4, and aim your pieces at the middle rather than the edges.

Develop your pieces quickly

Knights and bishops sitting on their starting squares contribute nothing. In the first eight to ten moves, get them out - knights usually to f3/c3 (or f6/c6 as Black), bishops to active diagonals. Avoid moving the same piece twice in the opening and resist grabbing pawns with your queen; an early queen gets chased around while your opponent develops for free.

Get your king safe

Castle early, almost always within the first ten moves. A king stuck in the center is the target of nearly every quick attacking loss in beginner chess. After castling, be slow to push the pawns in front of your king - they are its shield.

Core Tactics

Forks

One piece attacks two (or more) enemy pieces at once, so only one can escape. Knights are the classic forking piece because their jump is easy to overlook - a knight fork on king and queen wins the queen outright. Pawn forks against two pieces are just as deadly and cost almost nothing.

Pins

A bishop, rook, or queen attacks a piece that cannot (or should not) move because a more valuable piece stands behind it on the same line. A piece pinned against the king literally cannot move; a piece pinned against the queen usually shouldn't. Pinned pieces are also poor defenders - pile up attackers on them.

Skewers

The pin reversed: the more valuable piece is in front and must move, exposing the piece behind it to capture. A rook check that forces the king aside and then scoops up the queen behind it is the textbook skewer.

Discovered attacks

Moving one piece unveils an attack from another piece behind it - so your moving piece can create a second threat at the same time, and your opponent can only answer one. A discovered check is the most violent version: whatever the moving piece attacks is usually lost, because the check must be dealt with first.

Common Mistakes to Avoid

• Leaving pieces undefended. Most beginner games are decided by simply hanging a piece. Before every move, check what your opponent's last move attacks and what your intended move leaves loose.
• Bringing the queen out too early. Every attack on your queen is a free developing move for your opponent.
• Delaying castling. An uncastled king invites tactics down the central files.
• Making too many pawn moves. Pawns can't move backwards - every push creates permanent weaknesses. Develop pieces instead.
• Trading pieces when behind. If you're down material, trades only sharpen your opponent's advantage. Keep pieces on and create complications; trade when you're ahead.
• Forgetting stalemate. When you're winning big, always give the enemy king a legal move or a check - many won games end in a draw because the defender had nowhere to go.

Playing Against Our AI

The PlayVersusAI chess engine evaluates material, piece activity, and king safety, and searches deeper as the difficulty rises:

Frequently Asked Questions