Fourth Suit Forcing (to game)

When responder is an unpassed hand and rebids the fourth suit in an uncontested auction, his bid is artificial, shows 12+ points, and is game-forcing. For example,

1D - 1S - 2C - 2H

2H is artificial and a game-force. Opener's rebids, in order of priority, are:

FSF does NOT apply in the following situations:

From Connie DeLisle:

I like the Aces Scientific view of 4th suit forcing. The priorities are:

The reason 1 and 2 should be interchanged is that the 4sf bidder can bid his suit a second time to show 5. It may be too late otherwise to know if a stopper is in opener's hand for nt.