After your side opens 1NT you have Stayman and Jacoby Transfers to help you bid accurately to the best conract. Unfortunately the opponents will sometimes throw an overcall in and that plays havoc with your fancy conventions. So the lebensohl Convention was developed to counter that interference!
Assume partner has opened 1NT and the next player Overcalls 2 of a suit.
Here are your possible bids:
- Double : this is strictly for penalties (teach that guy not to interfere with YOUR side)
- any suit at 2-level : weak, Drop Dead type bid that partner should pass
- any suit at 3-level : 9+ points, 5+ card suit, forcing to game, may or may not be a jump
- cue-bid their suit : 9+ points, asks for a 4-card Major, (Stayman), with NO stopper in their suit
- 3NT : 9+ points, balanced, you want to play there ONLY if Opener can stop their suit
- 2NT : the lebensohl bid. Opener must bid 3♣ as a relay
After all the above except the 2NT bid, Opener bids naturally, trying to find the best fit.
After the 2NT bid, Opener relays with 3♣. Responder then bids as follows:
- pass with a weak hand and ♣ suit
- bid 3 of a suit as a Drop Dead bid if the suit could not have been bid at the 2-level earlier
- bid 3NT to play; this DOES show a stopper in the opponent's suit (Slow Shows Stopper)
- cue-bid the opponent's suit; this asks for a 4-card Major, (Stayman) but WITH a stopper in their suit
Lesson available (only the 1NT interference part).