Cannon behind the horse is one of the most famous mates in Chinese chess — for most players it is the first combination they ever play. The structure is clear, the effect is devastating, and every player needs it.

1. The structure

Two pieces do the work:

  • the horse — jumps to a key square and seals the general's escape squares;
  • the cannon — sits behind the horse (or on the same line), using a piece in between as a screen to give check.

Because the check cannot be avoided by moving the general — the horse has already closed those squares — the defender usually has no answer at all.

2. What the mate requires

  1. The horse must hold the key square, ideally covering two escape squares at once;
  2. The cannon must share a line with the general, otherwise there is no threat;
  3. There must be a screen, one piece between the cannon and its target;
  4. The defender must have no answer — if they can capture the cannon, interpose, or take the horse, the mate does not exist.

3. A typical sequence

With a red horse and cannon:

  1. The red horse jumps to the flank of the black general, sealing its escapes up and down;
  2. The red cannon swings onto the same line as the general, with a black piece in between;
  3. The cannon checks over that piece; the general can move neither up nor down — mate.

The key idea: the horse closes the door first, and the cannon delivers the last blow.

4. How to defend

  • Occupy the horse's key squares so it cannot establish control;
  • Use your general to drive the horse's leg, reducing its reach;
  • Trade off the horse or the cannon and the partnership disappears;
  • Keep a piece that can answer the check, either to interpose or to capture the screen.

5. Why it matters

Cannon behind the horse is common in both the middlegame and the endgame, and the chances multiply as pieces come off. When you are finishing a game, always check two things: can my horse and cannon make this mate, and is theirs about to?

How to practise: set up horse and cannon against a lone general and mate in the fewest moves. Then add advisors and elephants for the defender and work out how to break the defence first.

Read next: the double chariot and iron bolt mates.