1. The Fundamental Goal of Chess

Chess is a game of perfect information played between two players on an 8x8 checkered board containing 64 squares. The ultimate goal of the game is to checkmate the opponent's king.

A check occurs when a player's king is directly attacked by an enemy piece. When checked, the player must immediately eliminate the threat on their turn. If the king cannot move to a safe square, the attacking piece cannot be captured, and the check cannot be blocked, it is checkmate, and the game ends immediately.

2. The Chess Pieces: Values & Movement Rules

Piece Value Movement Pattern
King (♔/♚) Invaluable Moves exactly one square in any direction (horizontal, vertical, diagonal). Cannot move into check.
Queen (♕/♛) 9 Points The most powerful piece. Moves any number of unoccupied squares horizontally, vertically, or diagonally.
Rook (♖/♜) 5 Points Moves any number of unoccupied squares horizontally or vertically along ranks and files.
Bishop (♗/♝) 3 Points Moves any number of unoccupied squares diagonally along squares matching its color complex.
Knight (♘/♞) 3 Points Moves in an "L-shape" (two squares in one cardinal direction, one perpendicular). The only piece that can jump over others.
Pawn (♙/♟) 1 Point Advances one square forward (or two squares on its initial move). Captures one square diagonally forward.

3. Special Rules You Must Know

Castling (King Safety & Rook Activation)

Castling is the only move in chess where two pieces move in a single turn. The king moves two squares toward a rook, and that rook hops directly over the king to the adjacent square. Castling is permitted only if:

En Passant (In Passing)

When a pawn advances two squares from its starting position and lands adjacent horizontally to an enemy pawn, the enemy pawn may capture it diagonally forward as if it had only advanced one square. This capture must be executed immediately on the very next move.

Pawn Promotion

When a pawn reaches the eighth rank (the opponent's back row), it is immediately transformed into any piece of the player's choice (Queen, Rook, Bishop, or Knight). In 99% of cases, players promote to a Queen.

4. How One Chess Works

One Chess eliminates the tedious opening moves by dropping players straight into curated master game positions. Time controls, opponent Elo (from 1000 to 3000), and color assignments are completely randomized. At the end of every game, you can download your full standard PGN to analyze your decisions.