What is an interference tactic in xiangqi?
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
Putting a piece between a defender and the thing it is defending, so the connection is cut. Where a chariot or general is protecting a point along a line, dropping any piece onto that line breaks the defence outright. Against a cannon the same idea inverts: interference can hand the cannon a screen it did not have, creating a new threat rather than breaking one.
Cutting a chariot's defence
A chariot defending a point along a rank or file can only do so while the line stays clear. A piece placed anywhere on that line, even one that looks unrelated to the defended point, ends the defence immediately, whether or not the interfering piece itself is captured afterward.
The cannon complication
Because a cannon needs exactly one screen, interference against a cannon's own attacking line can go either way. Blocking its line removes the threat; adding the first piece onto an empty line between the cannon and a target creates one. Always check which case you are looking at before assuming interference helps you.
Related questions
Is this the same as a discovered attack?
Related. See discovered attacks for the case where the interfering piece is also the one that was blocking your own line.
Does material matter for the interfering piece?
Sometimes it is a genuine sacrifice; other times the interfering piece is doing useful work of its own and costs nothing.
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