Level 0.5 · Special Rules
Beyond the basics of how pieces move lie the rules that define the game's outcome — and a few surprising moves that trip up beginners. Master these six concepts and you know how chess actually ends.
White Rook on d1 gives check along the d-file.
Black King must move, block, or capture.
Rule 1
A King is in check when it is directly attacked by an enemy piece. Check is not instant defeat — but you must resolve it immediately. You cannot make any other move while your King is in check.
Three ways to escape check:
Move the King
Slide the King to any safe adjacent square not attacked by the opponent.
Block the Attack
Place a friendly piece between the King and the attacking piece. Only works against Rooks, Bishops, and Queens — not Knights or Pawns.
Capture the Attacker
Take the piece giving check with the King itself or another piece.
Rule 2
Checkmate ends the game. It occurs when a King is in check and there is no legal move to escape. The checkmated player loses immediately — the King is never actually captured.
In the diagram, both White Rooks form a mating net: the Rook on the 8th rank gives check, the second Rook covers the entire 7th rank, and the Black King has no escape square.
Key facts about checkmate:
Rook on a8 gives check. Rook on b7 seals the 7th rank.
Black King on h8 has zero legal moves — Checkmate!
Black King on h8 is NOT in check but has no legal moves.
g8 and h7 are both covered by the Queen. Draw!
Rule 3
Stalemate is a draw. It happens when a player has no legal move on their turn but their King is not in check. Unlike checkmate, the King is perfectly safe — there are simply no moves available to anyone.
Critical for winning players
Stalemate is a common trap that turns a winning position into a draw. If you are ahead in material, always verify your opponent's King has at least one legal move before delivering what you think is checkmate.
How stalemate differs from checkmate:
Checkmate
King is in check. No escape. → Loss
Stalemate
King is safe. No moves. → Draw
Rule 4
"In passing" — French
En passant is a special pawn capture that can only happen immediately after an opponent moves a pawn two squares forward from its starting rank, landing it beside your own pawn. You may capture it as if it had only moved one square.
Step by step:
Your pawn is on the 5th rank. The opponent's pawn is on its starting square (7th rank from their side).
The opponent plays their pawn two squares forward, landing immediately beside yours on the 5th rank.
On your very next move only, you may capture diagonally into the square the enemy pawn skipped. The captured pawn is removed from the board.
Miss the moment: If you don't capture en passant on the very next move, the opportunity disappears permanently.
Before
Black pawn just moved d7→d5.
White pawn on e5 may capture en passant.
After (e5×d6)
White pawn lands on d6. Black pawn on d5
is removed from the board.
Rule 5
Castling is the only move in chess where two pieces move simultaneously: the King slides two squares toward a Rook, and that Rook jumps to the square the King crossed. It is the fastest way to tuck your King into safety while connecting your Rooks.
Castling is only legal when ALL of these are true:
Short Castling
The King moves two squares toward the Kingside Rook (h-file). The Rook hops over to f1. Notation: 0-0. This is the more common of the two — fewer squares to clear and the King reaches safety faster.
Before
King on e1, Rook on h1
Clear path between them
After (0-0)
King lands on g1, Rook jumps to f1
King is tucked behind pawns
Long Castling
The King moves two squares toward the Queenside Rook (a-file). The Rook jumps to d1. Notation: 0-0-0. This requires clearing three squares instead of two, so it is slightly harder to achieve — but it can activate the Rook powerfully toward the center.
Before
King on e1, Rook on a1
b1, c1, d1 must all be empty
After (0-0-0)
King lands on c1, Rook jumps to d1
Rook now eyes the open d-file
You're ready
Jump into the puzzle trainer and apply everything you've learned against real game positions. The SM-2 algorithm will serve puzzles at your exact level and grow with you.