Chess is a two-player abstract strategy game played on an 8×8 board with 32 pieces (16 per side). The objective is checkmate: deliver an attack on the opposing king from which there is no legal escape. Recorded in essentially its modern form since the 15th century, chess is the most-played and most-studied board game in the world.
Each side starts with 1 king, 1 queen, 2 rooks, 2 bishops, 2 knights, and 8 pawns. White moves first; players alternate one move per turn. A move must either place the king out of check, prevent check, or simply develop a piece toward the opposing position. Three special moves — castling, en passant, and pawn promotion — round out the standard rules.
| Piece | Movement | Approx. value |
|---|---|---|
| King ♔ | 1 square in any direction; also castling, once per game | — |
| Queen ♕ | Any distance along ranks, files, or diagonals | 9 |
| Rook ♖ | Any distance along ranks or files | 5 |
| Bishop ♗ | Any distance along diagonals | 3 |
| Knight ♘ | L-shape (2+1); the only piece that jumps over others | 3 |
| Pawn ♙ | Forward 1 (or 2 from starting rank); captures diagonally; promotes on rank 8 | 1 |
King: 1 square in any direction (also castling). Queen: any distance along ranks, files, or diagonals. Rook: any distance along ranks or files. Bishop: any distance along diagonals. Knight: L-shape (2+1), the only piece that jumps. Pawn: forward 1 (or 2 from starting rank), captures diagonally, promotes on rank 8.
A special king + rook move done on one turn. Conditions: neither piece has moved; no pieces between them; the king is not in check; the king does not pass through or land on a square under attack. Kingside puts the king on g-file and the rook on f-file; queenside puts the king on c-file and rook on d-file.
When an enemy pawn advances two squares from its starting rank and ends beside your pawn, you may capture it as if it had moved only one square — but only on your very next move.
Checkmate ends the game with a win for the checkmating side. Stalemate — no legal moves but the king is not in check — ends the game in a draw. A common way beginners throw away winning positions.
For White, 1.e4 leads to open tactical games — try the Italian Game (1.e4 e5 2.Nf3 Nc6 3.Bc4) or Ruy Lopez (3.Bb5). For Black against 1.e4: Caro-Kann (1...c6) or French (1...e6) are solid. The principles — control the center, develop minor pieces, castle early, connect rooks — matter more than memorized lines below ~1500 Elo.
If 50 consecutive moves go by with no capture and no pawn move, either side may claim a draw. The counter resets on every capture or pawn push.
The engine has four strength tiers and three playing styles, and they combine freely — twelve distinct opponents in all. Strength controls how far ahead it looks; style controls what it wants.
| Opponent | Search | What it feels like |
|---|---|---|
| Novice | 1 ply | Takes what it can see this move and misses everything else. It will not hang a rook or queen outright, so games stay winnable rather than absurd. |
| Club | 2 ply | Sees a capture and the recapture. Loses pieces to two-move tactics like forks and skewers. |
| Expert | 3 ply | Punishes undefended pieces and simple tactics. Will not walk into a discovered attack. |
| Master | iterative deepening + quiescence | Deepens until its time budget runs out and extends every capture sequence to the end, so it cannot be tricked by an exchange that only looks good at the search horizon. |
| Style | Priorities | How to beat it |
|---|---|---|
| Aggressive | Piece activity near your king, material in your half of the board. Barely values its own pawn shield. | Trade off its attackers and open a file toward its own exposed king. |
| Positional | Mobility, healthy pawns, the bishop pair, central squares. The classical engine. | Create a locked structure where its extra mobility has nothing to attack. |
| Defensive | King safety above almost everything: castles early, keeps pawns in front of its king, keeps pieces home. | It concedes space. Take the centre, build up slowly, and open a second front. |
Strength and style can be changed in the middle of a game — they only affect the next move the engine searches. Switching sides starts a new game and flips the board so you always sit at the bottom.
The computer runs a minimax search with alpha-beta pruning. Every level searches one ply deeper at a time and keeps the best move from the last depth it finished, inside a fixed time budget: 0.4 seconds for Novice, 0.9 for Club, 2 for Expert and 3 for Master (which goes up to 5 ply).
Captures are tried first, ordered most-valuable-victim, least-valuable-attacker. It prefers the shortest forced mate. Legal moves are shuffled before each search, so equally scored moves vary from game to game.
Novice and Club do not always search. On 35% (Novice) or 8% (Club) of moves they play a random legal move instead, chosen from moves that do not put a rook or queen on an attacked square without capturing. Expert and Master never take a random move.
Material is counted as pawn 100, knight 320, bishop 330, rook 500, queen 900, plus a piece-square table for each piece type. On top of that it adds mobility, its knights, bishops, rooks and queen within four squares of your king (the queen counts double), the pawn shield in front of its own king, penalties for doubled and isolated pawns, a bonus for passed pawns that grows as they advance, a bishop-pair bonus, and a bonus for having castled. The playing style changes how much each of those terms weighs; material weights never change.
Click a piece to see its legal moves, then click the destination; clicking it again cancels. Two-player mode is for two people sharing one screen, shown from White's side.
Board Gaming Hub hosts a full-featured chess board in a single HTML page — no download, no account, no ads on the board itself. Play against a friend on the same device or practice openings solo. This guide is a compact rules refresher plus practical tips for browser play.
Move king two squares toward a rook; rook jumps to the other side. Requirements: neither piece has moved, no pieces between, king not in check, king does not pass through or land on an attacked square.
If a pawn advances two squares and lands beside an opposing pawn, that opposing pawn may capture it as though it moved only one square — but only on the immediately following turn.
A pawn reaching the far rank becomes queen, rook, bishop, or knight (almost always queen).
On mobile, use the built-in move list to review the game — small screens make blindfold calculation harder. If you undo by mistake, use the move list to step back mentally and replay from a stable position. For serious practice, set a timer externally; the hub board does not enforce clocks so casual play stays frictionless.