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Interference
Bidding interference by the opponents is a fact of life in bridge. This bidding system attempts to cope with it by providing methods to continue the partnership conversation.
1NT opening
We have discussed interference bidding already for the 1NT opening bid, but we will repeat it here. There are probably 100 conventions used to bid against an opening 1NT, most based on distribution and meant to cope with a strong NT.
1NT-(double): If Responder is weak (< 10 HCP) then Responder uses an escape bid. If Responder has 10+ HCP, Responder redoubles.
1NT-(2C): If Responder’s desired bid was also 2C, then Double (Stolen Bid Double). Otherwise make normal system bid.
1NT-(2D): If Responder’s desired bid was also 2D, then Double(Stolen bid Double). Otherwise make normal system bid. Partnership loses the ability to bid Stayman in this case.
1NT-(2H): If Responeder’s desired bid was also 2H, then Double(Stolen Bid Double). Otherwise make normal system bid. Partnership loses ability to bid Stayman and Jacoby Transfer to H.
1NT-(2S): If Responder’s desired bid was also 2S, then Double (Stolen Bid Double). Otherwise make normal system bid. Partnership loses ability to bid Stayman and Jacoby Transfers.
1NT-(2NT): This is usually the “Unusual NT” convention indicating 5/5 in the minors. Systems are off, bid naturally.
1NT-(3x): Systems are off, bid naturally.
There are additional conventions available for handling overcalls of NT, see Transfer Lebensohl
1C opening
The opening 1C bid often invites overcalls since it can be done cheaply at the 1 level. This is the major weakness of the LD Precision Club Bidding System. The overcall interferes with the normal constructive bidding sequence. So we have to find an alternative.
Without interference the responses to 1C opening are:
- 1D: <8 HCP
- 1H: 8-11 HCP
- 1S, 1NT, 2x: 12+ HCP and 5+ card suit if suit bid
With interference the responses are:
- Pass: <8 HCP
- 1C - (1X)
- Double - 8-11 HCP, no stopper, force to 3N+
- 1NT - 8-11 HCP, stopper, force to 3N+
- 2X - 12+ HCP, no stopper, force to game
- 2NT - 12+ HCP, stopper, force to game
- 1C - (2X)
- Double - 8-11 HCP, no stopper, force to 3N+
- 2NT - 8-11 HCP, stopper, force to 3N+
- 3X - 12+ HCP, no stopper, force to game
- 3NT - 12+ HCP, stopper, force to game
- 1C - (3X)
- Double - 8+ HCP, force to 3N+
- Any other bid: 12+ HCP and 5+ card suit if suit bid
All of the other sequences used still apply. The Double is not forcing, opener may pass for penalties.
There is one particularly interesting sequence:
1C-(overcall)-P-(P)-Double
What is happening here is opener is accomdating for the possibility that Responder has the same suit as overcaller and likes the idea of defending. If this is the case, Responder passes openers balancing double. If it is not the case, Responder treats the double as a Takeout Double and bids their best suit.
1H,1S, 1D opening bid
Use the same methods one uses in Standard American.
2C, 2D opening bid:
After overcall systems are off. Bid naturally.
