--- title: "Why Does the Cannon Need a Screen But the Chariot Doesn't? ยท Xiangqi Master" description: "It is simply how each piece is defined. The chariot captures the way it moves, while the cannon's capture rule is deliberately different from its move rule, and that split is what makes the cannon unique." url: https://xiangqimaster.com/blog/why-does-the-cannon-need-a-screen-but-the-chariot-doesnt updated: 2026-09-23 source: Xiangqi Master (https://xiangqimaster.com) license: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) --- # Why does the cannon need a screen to capture but the chariot doesn't? These answers restate the rules implemented by our open-source engine, which follows the WXF laws and is regression-tested against the official 110-diagram repetition casebook. Where an answer refers to a specific position, that position lives on the linked reference page, where the build verifies it against the engine before publishing. > Direct answer > > Because the two pieces are built on **different principles**, not variations of the same one. A chariot's capture rule is identical to its move rule: reach the first piece along a clear line and take it. A cannon's capture rule is deliberately **separate** from its move rule, requiring exactly one screen, and that split is the entire reason the cannon feels like nothing else in the game. ## What the split actually buys the game Every other piece in xiangqi, and every piece in chess, captures using the same logic it moves with. The cannon does not, and that single design choice creates threats that switch on and off as other pieces move, with no equivalent anywhere in the chess family. It is the one piece where you cannot read a threat simply by looking at where the piece could go. ## Why this is worth understanding rather than just memorising Once you see the cannon as a piece with two independent rulesets, one for moving, one for capturing, the seemingly strange behaviour (an open line has no attack; a blocked line might) stops being an exception to learn and becomes the obvious consequence of how the piece is defined. ## Related questions Does any other xiangqi piece have separate move and capture rules? No, the cannon is the only one. Every other piece captures exactly the way it moves. Is this unique among all board games, not just chess? Essentially, yes, within the chess family. Korean janggi has a similar cannon, but even that one needs a screen just to move, which xiangqi's does not. ## Related xiangqi resources How the cannon moves Captures only by jumping exactly one screen How the chariot moves Like a rook, and the strongest piece on the board Xiangqi vs chess What carries over from western chess, and what does not ## Try it on a real board Reading an answer is one thing; playing it is another. Free, instant, and nothing to install.