Double bishop mate

In a double bishop mate, one bishop checks the king while the other controls squares the king could use to escape. It is checkmate because the king cannot move to safety, capture the checking piece, or block the attack.

The identifying picture is a pair of parallel diagonals running close to the king. Since each bishop stays on one square color, the two bishops normally divide the light and dark escape squares between them. The defender's own pieces or the edge of the board usually close the remaining routes.

Parallel diagonalsCrossed diagonals

Two diagonals moving together

8

7

6

5

4

3

2

a1

b

c

d

e

f

g

h

The bishop on h3 attacks c8 and controls d7 along the same line.

Check on one line, escapes covered on the next

The two diagonals run in parallel: one carries the check and the other covers the edge escapes.

1. The bishop on h3 attacks c8 and controls d7 along the same line.
2. The bishop on h2 covers c7 and b8 along the parallel diagonal.
3. The black bishops on b7 and d8 occupy the remaining escapes.

Do not identify the pattern merely because two bishops are attacking. Trace the checking bishop, then verify every square covered by the second bishop and every possible defense. This differs from Balestra mate, where a bishop mates with the queen controlling the king's movement.