The sequence only knew accounts, lines, periods and closes, but that is no longer where money moves: invoices, bills, their payments, write-offs and voids are now first class, and the draft-state commands decide whether an entry exists at all. Op gains each of them, on the same Ledger the store wraps, with random parties, dates and amounts (including the raw-decimal extremes). The invariant after every sequence gains B-38: each control account equals its documents as of three dates, and a control check too large to compute is a refusal, never a difference. That is the identity that would catch a payment tagged to the wrong document, or one that went unmatched, which the trial balance alone cannot see.