2/1 Game Forcing - Other 2/1 Features

Other 2/1 Features

Use of the 2/1 system usually implies (at least) the following additional agreements:

• Five card majors, i.e. major suit openings require at least a five-card suit;
• Limit raises of major suit openings, i.e. the jump raise 1♠ – 3♠ or 1♥ – 3♥ shows a game-invitational hand with at least four-card support (unless Bergen raises are used);
• Inverted minor raises, in which a jump raise of a minor suit opening is a weak preemptive bid, while a single raise is strong and forcing for one round;
• Jacoby transfers over 1NT opening;
• Jacoby 2NT, showing strong support with 4 or more cards;
• Splinter bids;
• New minor forcing;
• Fourth suit forcing and artificial.

Some also utilize Bergen raises.