◇ Just read — no move neededOne rank apart, one rank fatal
双车错 — the staggered chariots — is the two-chariot mate where the killers stand on adjacent ranks. The first chariot checks along the king's rank; the king's only legal reply is to step off that rank. But the square he lands on sits on the second chariot's rank — and stepping back is barred because the first chariot still owns the rank he came from. Between the two blades there is exactly one square, and it is already occupied by the king.