How to Checkmate with Two Bishops: The Bishop Wall and Corner Mate

King and two bishops (one on light squares, one on dark squares) against a bare king is always a win, but you can only mate in a corner. In the middle of an edge the king always slips away. The method: put the bishops side by side so their diagonals form a wall, and bring your king up to help. It takes a few more moves than the queen or rook mate, so set it up and practice it when you play chess online.

Key position

How to play it

Step 1: put the bishops side by side to build a wall

With the two bishops on neighboring squares, one controls light-square diagonals and the other dark-square diagonals. Together they form a wall the enemy king can't cross.

The bishops end up side by side on d5 and e5. They cover c4, d4, e4 and f4, so the black king can't cross the 4th rank and is stuck on the bottom three ranks.

Step 2: bring the king up and drive the enemy king to a corner

Once the wall is up, the white king joins the bishops. Every move takes away a little more space, herding the black king along the edge toward a corner.

The white king reaches f3, and the bishops drop back to c1 and c2 to close the door. The black king is now squeezed onto the right side of the first rank, close to the h1 corner.

Step 3: mate in the corner

The black king is driven into h1. Be4 checks along the diagonal, the bishop on e3 covers g1, and the white king covers g2 and h2. Checkmate.

Common mistakes

When the black king is trapped in the corner with only a square or two left, it's easy to let a bishop take away the last square without giving check. That's stalemate.

Mistake: Bc4?? covers g8. The black king on h8 isn't in check and has no square left. Stalemate.

The right move here is Bh6 (or Bc5). Let the black king shuffle between g8 and h8, then mate with Bc4+ and Bg7:

Bh6 covers g7, so the king has to go to g8. Bc4+ drives it back to h8, and Bg7 is mate.

The other big mistake is losing a bishop. King and one bishop can't mate, so it's an immediate draw.

Practice puzzles

White to move. The black king is in the a1 corner. Mate in one.

Show answer

1. Bb2# The dark-squared bishop checks from b2. The white king covers a2, the light-squared bishop on f5 covers b1, and the king can't take on b2 because the white king protects it. Checkmate.

White to move. The black king only has b1 left. Don't stalemate: give it room first.

Show answer

1. Ba3 For example Ba3 (Bf4 also works). The king has to go to b1, Bf5+ sends it back to a1, and Bb2 is mate. Bf5?? or Kc2?? takes away b1 and it's stalemate.

FAQ

What if both bishops are on the same color?

If both bishops run on light squares (say, after an underpromotion), they can never cover a dark square, so mate is impossible and it's a draw. The two bishops mate means one light-squared and one dark-squared bishop.

How many moves does the two bishops mate take?

According to the tablebase, at most 19 moves from the worst starting position. That's more than the queen or rook, but there's still plenty of time within the 50-move rule.

Why does it have to be a corner?

Bishops control diagonals, so in the middle of an edge the king always has one square to slip out. Only in a corner can two bishops and a king cover every square.

Try it yourself

Once you can mate with two bishops, try the harder bishop and knight mate. All the endgames are in Chess endgames. Or head over to chess online, play the computer, and keep both bishops into the endgame to try it out.

Practise in a game