Fourth suit forcing is a convention. This convention is alertable. In non-competitive auctions, it often happens that three suits are bid and no fit is found, as in The opener's 1♠ bid was forcing. Responder now has several options: * With a minimum, responder can rebid one of the previously mentioned suits or notrump at the cheapest level. * With any more, the responder must either make a jump rebid of a previous suit or notrump, or bid 2♦. There are a number of different ways to treat this convention: In all cases, the fourth suit is forcing and artificial.