How do you decide which piece to trade 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
Start from rough point value so you don't simply give material away, then weigh what the trade actually changes on the board: whose remaining pieces get more active, whose king becomes safer or less safe, and whether you are opening a file your opponent needed more than you did.
Trading to simplify versus trading to attack
If you are ahead in material, trading pieces of roughly equal value generally helps you, since it reduces your opponent's attacking chances while your advantage remains. If you are attacking, keeping pieces on the board, especially cannons and horses that need coordination, usually serves you better than simplifying.
Pieces that gain or lose value with fewer pieces left
A horse tends to get stronger as the board empties, since fewer pieces block its legs; a cannon tends to get weaker, since fewer pieces remain to act as screens. Knowing which direction the position is heading should influence which of the two you are more willing to trade away.
Related questions
Is it ever right to trade a stronger piece for a weaker one?
Yes, if the resulting position is better for you, such as removing your opponent's only active piece or breaking up their defence.
Should I avoid trading my last cannon?
Not automatically, but check first whether you still have enough attacking resources without it.
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