Why do red and black use different characters 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
So you can tell the armies apart at a glance. Five pairs always differ: 帥/將, 仕/士, 相/象, 炮/砲, 兵/卒, and many sets also write 傌/馬 and 俥/車. Some pairs sound alike, others do not (帥 shuài, 將 jiàng), and the pieces move identically — it is a visual convention, not a rule difference.
The pattern behind the pairs
Red's characters tend to be the more formal or military-flavoured ones: 帥 (marshal) against 將 (general), 仕 (officer) against 士 (scholar), 兵 (soldier) against 卒 (conscript). Several of Red's take the 人 radical — 傌, 俥 — which is a quick way to recognise the side.
The cannon's two radicals
炮 and 砲 are both used, and which side gets which varies between manufacturers and books. 砲 has the stone radical (older siege engines threw rocks); 炮 has the fire radical (gunpowder). Nothing about play changes either way.
Related questions
Do the different characters move differently?
No. The pairs are purely cosmetic.
Which colour is 帥?
Red, conventionally. Black's general is 將.
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