What is 順炮 (same direction cannons)?
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
順炮 happens when Red plays a central cannon and Black answers with a central cannon from the same side. Both end up on the central file pointing at each other with only soldiers between. The position is symmetrical and extremely sharp, and Red's extra move usually means Red attacks first.
Why symmetry makes it dangerous
Every tactic Red finds, Black has too — one move later. In a position where both sides attack the same points, that single move is worth a great deal. The player who copies moves without understanding them loses to a tactic that arrives one tempo early.
順炮 or 列炮
Placing the cannon on the same side gives 順炮 and a symmetrical race. Placing it on the other side gives 列炮, an unbalanced game where the two players attack on different wings. Neither is better; most players learn one and stay with it.
Related questions
Is 順炮 good for beginners?
Instructive, because symmetry makes tempo obvious. Also unforgiving — one slow move hands over the attack.
Should I trade the central cannons?
Only for a concrete reason. Trading releases the tension and usually helps whoever was worse.
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