Jack (playing card)
（重定向自Jack of Spades）
A Jack, also Knave /ˈneɪv/, is a playing card which, in traditional French and English decks, pictures a man in the traditional or historic aristocratic dress generally associated with Europe of the 16th or 17th century. The usual rank of a Jack, within its suit, plays as if it were an 11 (that is, between the 10 and the Queen). As the lowest face (or "court") card, the Jack often represents a minimum standard — for example, many poker games require a minimum hand of a pair of Jacks ("Jacks or better") in order to continue play.