--- title: "The Double Cannon Mate (重炮) in Xiangqi · Xiangqi Master" description: "Two cannons stacked on one file, the front one screening for the one behind. Why the general cannot capture, block or run, on a position verified by the engine." url: https://xiangqimaster.com/tactics/double-cannon-mate updated: 2026-09-07 source: Xiangqi Master (https://xiangqimaster.com) license: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) --- # The double cannon mate (重炮) Every position, move and legality claim on this page is verified programmatically against our open rules engine, which implements the WXF laws and is tested against the official 110-diagram repetition casebook. > Direct answer > > In 重炮 two cannons stand on the same file as the enemy general. The front cannon is the screen the rear cannon needs, so the rear cannon gives check. It is mate when the front cannon is defended, so the general cannot take it, and the general's own advisors block its way sideways. ## The pattern Two cannons, one file, one behind the other. The rear cannon does the checking and the front cannon is the screen that lets it. The front cannon must be defended by something, because otherwise the general simply captures it. Red to play. The rear cannon is not on the file yet. Red to play and mate in one. 重炮. The black advisors, which usually protect the general, are what leave it with nowhere to go. > Diagram: Xiangqi position. Red: chariot a8, cannon e8, cannon a6, general d0. Black: advisor d9, general e9, advisor f9. Red to move. ## The three conditions This mate needs all three of these at once, and it fails without any one of them: - **The front cannon is defended.** Here a chariot on the same rank does it. Without that, the general captures the cannon and the position is nothing. - **Nothing can come between.** The front cannon stands directly in front of the general, so there is no empty point for a defender to interpose on. - **The general cannot step sideways.** In the position above its own advisors are in the way. This is the small irony of the pattern: the pieces that guard the general are what trap it. ## How it turns up in games Most double cannon mates come from a position where one cannon is already aimed at the enemy general down the central file, which is the normal result of the [Central Cannon](https://xiangqimaster.com/openings/central-cannon) opening. The second cannon joins later, and the mate arrives in one move from what looked like an ordinary attacking position. Because of that, the warning sign for the defender is simple and worth checking every move: if an enemy cannon is on your general's file and a second cannon can reach that file, count the squares before you do anything else. ## Common mistakes #### Leaving the front cannon undefended The general captures it and the attack disappears. Work out what defends the front cannon before you commit the rear one. #### Leaving an empty point in front of the general Any gap gives the defender a square to block on, and a blocked file is not a check. The front cannon belongs immediately in front of the general. #### Assuming advisors always help the defender In this pattern they are the reason the general cannot move. When defending, look at whether your own pieces are taking away your general's last points. ## Related questions What is 重炮 in xiangqi? Two cannons on the same file as the enemy general, one directly behind the other. The front one screens for the rear one, which delivers the check. The name means stacked or doubled cannons. Why can the general not capture the front cannon? Because in the mating version something else defends it. A general may not move to a point that is attacked, so a defended cannon standing next to it is untouchable. How is this different from horse behind cannon? Both use a screen to check with a cannon. In [馬後炮](https://xiangqimaster.com/tactics/horse-behind-cannon) the screen is a horse, and the horse also covers the escape points. In 重炮 the screen is a second cannon, and the escape points are blocked by the defender's own pieces instead. ## Related xiangqi resources Horse behind cannon The other classic cannon mate Cannon tactics Screens, batteries and discovered attacks The Central Cannon Where the first cannon usually comes from ## Put it into practice Play a game against the computer or a real opponent. It is free, it starts instantly, and there is nothing to install.