Hollow cannon
空头炮 · kōng tóu pào · empty headed cannon
A cannon on the middle file with nothing between it and the enemy General, which paralyses the defence and usually wins.
When the central file empties and your cannon sits on it facing the General, the defender is in permanent trouble. Any piece that steps onto the file becomes a screen and lets the cannon capture, so the defender cannot block. Any piece already there is pinned.
It is one of the most feared shapes in xiangqi, and the reason experienced players guard the middle file even when nothing seems to be happening there.
Getting one is usually worth material. Giving up a soldier or even a horse to strip the middle file bare is a standard idea, because the paralysis that follows is worth more than the piece in almost every position with attackers left.
In practice
Do not let your central soldier and central defenders all disappear at once. The hollow cannon arrives the move after the file opens, not before.
Related terms
- Cannon炮 / 砲A piece that moves like a chariot but can only capture by jumping exactly one piece, called the screen, on its way to the target.
- Screen炮架The single piece a Cannon jumps over in order to capture, which may belong to either player.
- Iron gate bolt铁门栓A mate where a cannon on the middle file freezes the palace and a chariot delivers the blow the defender cannot answer.
- Palace九宫The three by three square marked with a cross at each end of the board, which the General and the two Advisors may never leave.