The ojigi hanko, the bowing seal, is a personal seal stamped at a slant on a document, so that it leans toward the seal of the superior beside it. A business guide by Money Forward calls it one of the business manners that some companies treat as a rule.
Its origin is uncertain. A writer in the magazine President says that, by one account, a department of a major city bank made it a rule, and the rule spread as a rumor. He adds that even this is not certain.