What is the same-direction cannons opening in xiangqi?
These answers restate the rules implemented by our open-source engine, which follows the WXF laws for movement, checkmate and both repetition rulings: a side that forces a repetition by perpetual check or perpetual chase loses rather than drawing. The chase half has not been validated against the official casebook. Where an answer refers to a specific position, that position lives on the linked reference page, where the build verifies it before publishing.
Direct answer
It is 順炮: Red plays a central cannon and Black answers with a central cannon from the same side of the board, so both cannons sit on the central file pointing at each other. The position is symmetrical and sharp, and Red's extra move usually means Red attacks first. Answering from the other side gives 列炮 instead.
Why the symmetry makes it sharp
Every tactic Red finds, Black has too, and the only difference is that Red moves first. That single move is worth a great deal when both sides are attacking the same points, which is why copying moves without understanding them is the usual way to lose it.
Same direction against opposite direction
Black's choice of side decides the character of the game. The cannon from the same side gives 順炮 and a symmetrical race; from the other side it gives 列炮, where the two attacks point at different wings. Neither is better, and most players learn one and stay with it.
Related questions
Is this a beginner-friendly opening?
It is instructive, because the symmetry makes it obvious when a tempo matters. It is also unforgiving, since a single slow move hands the opponent the attack.
How does it compare to 列炮?
列炮 is the opposite-direction version: less symmetrical, with each side attacking where the other is not defending. 順炮 is the kinder introduction, because the plans are more obvious and mistakes punish less quickly.
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