Saturday, August 17, 2002 6:00 AM

Thrump Doubles

PITBULLS:

Marty Bergen has modified negative doubles at the 3 level. He has the bid primarily as looking for THRee notrUMP and calls them Thrump doubles. On most hands where partner has a stopper in the opponent’s suit, you would like him to bid 3NT. If no stopper in their suit , treat the double as “normal” and bid your major.

Thrump Doubles are not incompatible with normal major suit showing doubles at the 3 level.

You hold AKxx AKxx xxx xx and partner opens 1♣ and there is a 3♦ pre-empt. You still double and partner bids 3NT . You miss your 4-4 major games ( possibly) but 3NT is 9 tricks and 4-1 breaks in the majors are common with the distribution displayed at the table. If partner does not have a stopper bidding carries on naturally and you find your major fit.

Playing Thrump doubles there is no more “implied Q bids “ in these negative double auctions . You double and partner bids 3♠ and you bid 4♦ . This is not a Q bid implying spades , but a long diamond suit you were hoping was useful in 3NT . Say you have Ax xx J10x AQJ109x and partner opens a heart and RHO pre-empts 3♦. Make a negative double ! If partner does not bid 3NT you bid 4♣ and you are no worse off than you were originally with a direct 4♣ bid. You had a chance to get to 3NT from the correct side though with your double..

Here is an excerpt from the net by the author Marty Bergen.

Thrump Doubles

“Thrump doubles,” as described here, were invented by yours truly. While they certainly are different, experience has shown that they are essential at the three level.

What is a thrump double and why do we need them? The discussion of the bidding on this hand will clue you in.

ª Q7 © Q2 ¨ 1087 § AKQJ75

Once your partner has opened the bidding, you are thinking about 3NT. In fact, I will bet that is the case regardless of which suit your partner opened. You will show your clubs and points and hope partner bids notrump sooner or later.

Nice plan. Now suppose that your RHO jumps to 3¨, 3© or 3ª before you are able to make your first bid. Are you going to give up on the 3NT contract you were heading for? If you make the “normal” 4§ bid, do you expect partner to provide the five tricks you will need to bring home 5§?

What is my suggestion? Make a negative double. However, instead of defining it as looking for the unbid major(s), think of it as looking for THRee notrUMP. On most hands where partner has a stopper in the opponent’s suit, you would like him to bid 3NT.

When is this needed? When the enemy’s natural jump overcall reaches 3¨, we cannot necessarily show our suit without going past 3NT. Here are the 10 auctions where the opponent has made a natural, preemptive jump overcall above 3§ and below 3NT.

1§ - (3¨) 1§ - (3©) 1§ - (3ª)

1¨ - (3¨) 1¨ - (3©) 1¨ - (3ª)

1© - (3¨) 1ª - (3©) 1© - (3ª)

1ª - (3¨)

Must you have a solid suit? Absolutely not. A thrump double

would be totally appropriate after 1© - (3ª) with:

ª 864 © 65 ¨ AQ754 § AQ2 or

ª 93 © K7 ¨ KQ10865 § KQ8 or

ª 63 © A2 ¨ 852 d AK10854

Now you are responder after 1§ - (3©).

ª K3 © 84 ¨ AKQJ5 § J753

(Double, hoping partner bids 3NT.)

(Forget your spades. You have hearts stopped so bid 3NT.)

(Once in a blue moon you will have a great hand with a stopper in the opponent’s suit. In that case, you can start with a negative double and then explore for slam.)

Thrump Double Summary

ü Tells opener to bid 3NT when he has a stopper in the opponent’s suit.

ü Says nothing specific about responder’s holding in the unbid suits.

ü Almost always denies a stopper in the opponent’s suit.

ü Responder denies a five-card major that he could have bid at the three level.

ü Promises at least 10 HCP and denies three-card support for opener’s major.

Worth noting: responder could have a very long minor.