Is the cannon considered a major piece like the chariot, or grouped with the minor pieces?
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
With the big pieces. Chinese commentary calls the chariot, horse and cannon 大子, the big pieces, as against advisors, elephants and soldiers. It is a playing convention, not a rule, and it does not split the way chess does: on the usual scale the cannon (4.5) sits close to the horse (4) and well below the chariot (9), and its value swings more with the position than either.
Why the chess labels don't map cleanly
Chess divides pieces largely by raw mobility on an empty board. Xiangqi's cannon breaks that model outright, since its capturing power depends entirely on screens rather than open lines, so a strength-based label that fits in one position can fit poorly in another just a few moves later.
What players actually say
Beyond the big-piece grouping, xiangqi commentary usually talks about specific piece types and their point values, chariot, cannon, horse, and so on. If you want a rough equivalent for a chess player's intuition, the cannon lands closest to a rook that needs help to attack: clearly below the chariot, and close in value to the horse.
Related questions
Is the chariot the only piece that clearly counts as a major piece?
By strength, yes: it is the strongest single piece type and the closest equivalent to a chess rook. In the Chinese grouping, though, the horse and cannon are big pieces too.
Where do the horse, elephant and advisor fit?
The horse is one of the big pieces, close in value to the cannon. The elephant and advisor are weaker and mainly defensive, since neither can cross the river.
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