Chess: moves that keep your king safe

Two checks for a legal move

A legal chess move has two jobs. It must follow the piece's movement rule, and it must leave your own king safe. These are two different checks. A rook might travel in a perfectly straight line and still make an illegal move if that line uncovers an attack on its king.

Straight lines and diagonals

Rooks move along rows and columns. Bishops move along diagonals. A queen can use either kind of line. These pieces cannot pass through another piece. They may capture an opponent by landing on its square. They cannot land on a friendly piece and ask it to squeeze over a little.

Pawns do not capture forward

A pawn usually moves one empty square forward. From its starting rank it may move two, if both squares are empty. Its ordinary capture is one square diagonally forward, not straight ahead. Pawns have special promotion and en passant rules too. The guided game gives those rules their own practice positions.

A knight takes the L-shaped route

Our white knight is on d four. A knight moves two squares in one direction and one at a right angle. It can jump over other pieces. From d four, f five is an L-shaped destination. It holds a black pawn, so the knight can land there and capture it.

Pause: a jump is not a free pass

Now inspect e six in the same position. It is an L-shaped destination from d four, but it holds a white pawn. Pause. Can our knight land there? Count all eight possible L-shaped destinations and remove any friendly-occupied square. How many legal destinations remain for this knight in this position?

Seven choices, not eight

The knight cannot land on its own pawn on e six. That leaves seven legal destinations. The picture now shows the knight after capturing the black pawn on f five. The white pawns stay where they were. A knight can jump over traffic, but a friendly piece still owns its parking space.

The king needs a safe square

Here White's king is on e one and Black's rook is on e eight. The file between them is empty, so the king is in check. White must end that attack with the next move. A king moves one square, but may not enter an attacked square. Kings are never captured.

A shield must keep shielding

In the worksheet position, a white rook starts on e two and shields that king. Moving the rook to e three keeps the shield on the same file, as shown here. Moving it sideways to f two would expose the king and is illegal. Following rook movement alone is not enough.

A surprising move for a pinned piece

Fun fact: a pinned piece can sometimes still move. Our rook may move along the e file, keeping the king protected. It can even capture the attacking rook on e eight. Do not memorize that pinned means completely frozen. Inspect the attack line and check what happens after the move.

Name the rule and the reason

Continue to Choose a Knight Move below. Then try Keep Your King Safe for the shield position. In Chess Workshop, explain both parts of a move: how the piece travels, and why your king stays safe. If a move is not allowed, use the explanation to choose again. Trying again is practice, not defeat.