How do you verify your general is actually checkmated rather than just in a difficult check?
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
By working through the same three options every time, systematically. Before accepting that a position is checkmate rather than merely a hard check, confirm in turn that the checking piece cannot be captured, that its line cannot be blocked, and that the general has no legal square to move to, checking every neighbouring point individually rather than trusting a first impression.
Why a quick glance is not reliable
Under pressure it is easy to see one obvious defensive try fail and assume the whole position is lost, when a different, less obvious option was actually available. A square that looks unsafe at first glance can turn out to be perfectly legal once you check it properly against every attacker, not just the one that is currently giving check.
The order worth checking in
Start with capturing the piece that is giving check, since that is often fastest to rule in or out. Then check whether anything can legally interpose on the line, remembering that a horse check is blocked on the horse's leg point, and that a double check must be answered against both attackers with one move. A cannon check also ends if its screen moves away. Finally check every point the general could physically move to, testing each one fully rather than stopping at the first that looks unsafe.
Related questions
Is it worth checking this before resigning in a casual game?
Yes, a surprising number of apparent mates in casual games turn out to have a resource the losing side missed under pressure.
Does an engine or app do this check automatically?
Yes, reliably, which is one of the clearest practical advantages of playing somewhere the legality is enforced for you.
.