The cannon needs a screen to capture, so it loses power as pieces leave the board. Learn how cannon endgames really work in Xiangqi (象棋, Cờ Tướng) and why a supporting soldier is decisive.
The cannon is the most paradoxical piece in Xiangqi (象棋, Cờ Tướng). It moves like a chariot, sliding freely along ranks and files, but it can only capture by jumping over exactly one intervening piece, its screen. In the crowded middlegame this makes it a fearsome attacker with targets everywhere. In the endgame the opposite is true: as pieces come off the board, screens vanish, and a cannon can find itself with nothing to jump over and no way to threaten anything.
This single quirk defines all cannon endgames. A lone cannon that looks powerful can be utterly toothless if the enemy simply refuses to provide a screen. Understanding when the cannon can force a win, and when it needs help, is essential knowledge that saves half-points and wins games you might otherwise misplay.
Why the Lone Cannon Is Weak
A cannon alone against a bare king cannot deliver checkmate, and often cannot even force meaningful progress, because the defender can keep the board clear of screens. To check with a cannon you need a piece between the cannon and the enemy king; if the defender controls that middle point, no check exists. This is why the lone cannon, despite its long range, is far weaker in the endgame than the chariot it superficially resembles.
The defender's method against a lone cannon is simply to avoid providing screens and to keep the king safely maneuvering within its palace. The attacker cannot manufacture a screen out of nothing. This is the fundamental lesson: the cannon's power is entirely dependent on the presence of other pieces, so as the board empties, always ask whether your cannon still has, or can create, a screen for its threats.
The Cannon Needs a Partner
Because of its screen requirement, the cannon is at its best in the endgame when paired with another piece. A cannon and a single soldier, or a cannon and an advisor used cleverly as a mounting platform, becomes genuinely dangerous. The classic pairing is the cannon plus its own advisor acting as a permanent screen: the advisor sits on the central palace point, and the cannon fires over it to check or pin the enemy king along the file.
This "cannon behind advisor" battery is one of the most important attacking mechanisms in the whole endgame. By keeping a friendly piece as a fixed screen near the enemy king, the cannon regains the checking power it lacks when alone. When you reach a cannon endgame, your first strategic question should be: which of my pieces can serve as a reliable screen, and how do I position it near the enemy palace to unlock the cannon's threats?
Cannon and Soldier Against Advisors
One of the most practical cannon endings is cannon plus soldier against a defense of advisors. With correct technique this is often winning, because the soldier and cannon combine roles: the soldier can act as a screen for the cannon or advance to attack the palace directly, while the cannon delivers checks over available screens. The interplay between the two attackers is what breaks the defense apart.
The winning plan usually involves advancing the soldier across the river, where it gains sideways movement and becomes a strong attacker able to approach the palace from the flank. Meanwhile the cannon uses the soldier, an advisor, or even the enemy king's own defenders as screens to force material gains or checkmate. Precise coordination is required, and losing the soldier prematurely often converts a win into a draw, so guard it carefully while you maneuver.
Practical Cannon Technique
The practical takeaway is to always evaluate a cannon by its screens, not by its range. Before trading pieces in a position heading toward a cannon endgame, ask whether the resulting position still gives your cannon useful screens near the enemy king. If it does not, you may be trading into a drawn or even lost position despite nominal material equality. Many players lose cannon endings simply by ignoring this.
Defensively, remember the flip side: against an enemy cannon, deny screens, keep your king mobile, and be willing to trade off the piece that serves as the cannon's platform. Practicing cannon endgames on XiangqiPlay against the computer quickly builds an instinct for when the screen piece makes the cannon deadly and when its absence makes the cannon harmless. That instinct is worth many points over a competitive career.