Chess

The royal game - checkmate the enemy king to win

You
White
AI
Black
Your turn - move a piece
How to Play Move: 0

How to Play Chess

Chess is a two-player strategy game on an 8x8 board. Each side commands sixteen pieces - eight pawns, two knights, two bishops, two rooks, a queen, and a king - and the goal is checkmate: attacking the enemy king so that it has no legal escape. Click one of your pieces to see its legal moves, then click a highlighted square to move. Every rule of tournament chess is here, including castling, en passant captures, pawn promotion, and draws by stalemate, insufficient material, or the fifty-move rule.

On PlayVersusAI you play White against a Black-piece AI engine that actually searches ahead - it evaluates material and piece placement, prunes bad lines, and punishes hanging pieces. You can also challenge a friend in real-time online multiplayer, where the host takes White and the board flips so each player sees their own army at the bottom.

Strategy Tips

Read the full Chess guide →

Playing Chess on PlayVersusAI

Full chess, with the complete ruleset rather than a simplified subset: castling on both sides with all its conditions, en passant capture, underpromotion as well as promotion to a queen, stalemate, and draws by repetition and the fifty-move rule. Legal moves are highlighted, and you cannot play a move that leaves your own king in check.

The engine evaluates positions using material values combined with piece-square tables, so it understands that a knight in the centre is worth more than one on the edge and that pawns grow in value as they advance, alongside terms for king safety and pawn structure. It searches with alpha-beta pruning and orders captures and checks first to search deeper in the time available.

What's on This Page

Easy hangs pieces and is a reasonable opponent while you learn how the pieces move. Medium plays sensibly and will punish a hanging piece. Hard finds tactics several moves deep — forks, pins and skewers appear out of nowhere if you leave the geometry available. AI Training is a solid club-strength opponent within its search horizon.

Mistakes That Lose Games

Chess Questions

How strong is the chess engine?
Roughly club strength on the hardest setting. It calculates tactics well within its search depth and knows the full rules, but it has no opening book and no endgame tablebases, so strong players can out-manoeuvre it in quiet positions and in king-and-pawn endings. We would rather state that plainly than oversell it.
Are castling and en passant supported?
Yes, both, with their full conditions — castling is blocked if the king has moved, if the rook has moved, if the path is occupied, or if the king would pass through or land on an attacked square. En passant is offered only on the move immediately following the relevant double pawn push.
Can I promote to something other than a queen?
Yes. When a pawn reaches the final rank you choose the piece, and underpromotion to a knight, rook or bishop is available. It is occasionally the only way to avoid stalemating your opponent.

For the complete rules, the deeper strategy and the history of the game, read the full Chess guide, or browse guides for all 20 games.