Thursday, September 15, 2005 10:24 AM

DNA Analysis

PITBULLS:

The DNA molecule that makes up all Bridge hands are patterns. DNA analysis in Bridge is to discover which of the 39 building blocks the cell structure of the particular hand has that concerns you. The analytical tools at your disposal are bidding , opening leads , signals and the simple act of following suit. Here are 3 hands that show how Bridge scientists discover the DNA of a particular hand.

You are in 7NT vul playing the last hand of an important KO event. You get the spade 10 lead and the hands are as follows:

♠ AKx ♥ Qxx ♦ AQx ♣ AQ109

♠ Qxx ♥ AKx ♦ KJx ♣ Kxxx

This hand looks pretty simple. The only thing that can go wrong is a 4-1 club break but from which side ? DNA analysis to the rescue. Lets discover if we can what DNA molecule the opponents have that make up their two hands. Lets start with the spades. You cash 3 rounds and RHO shows out discarding a diamond. The spade molecule is 5-3-3-2 . We have discovered that LHO has 5 in her hand pattern that makes up her DNA structure. How about hearts ? You cash all your hearts and everybody follows with LHO playing the heart jack. OK lets try diamonds next the suit in which west discarded. Everybody follows to diamonds so that DNA molecule is complete. 4-3-3-3 and LHO had 3 diamonds. We do not have a complete analysis of the LHO molecule but we getting close enough to guarantee our contract. 5-3-3-? As LHO can not hold more than two clubs ! You go to the board and cash the club Ace and queen and LHO shows out ! The final analysis 5-4-3-1 and RHO gets finessed out of her club jack to bring the contract home.

Two recent hands from matchpoints in which Tom Gandolfo played the role of scientist. Tom is in 5♦X which he must hold to down 3 NV against the vul 4♠ game.

♠ xx ♥ x ♦ Kxxxx ♣ AQxxx

♠ Qxx ♥ xxxxx ♦ J1098 ♣ x The auction went 1♥-2NT-3♠-5♦ P-P-X-P . They lead a small

spade and RHO cashed the spade AK and played Ace and a small heart which Tom ruffed on the board. Tom noted that although LHO opened the bidding the doubler has shown up with AK & an Ace thus far. Does this give the opener the Ace and queen of diamonds ? DNA analysis required to answer that question. Tom played the club Ace and ruffed a club back to his hand and noted that the club king which must be in openers hand did not fall. Tom cashed the spade queen and LHO followed with the jack. OK opener is 3-5-? With at least 3 clubs so Tom leads the diamond jack and LHO plays small do you finesse ? Not if your DNA analysis is correct , as LHO can only hold two diamonds ! Tom goes up with the King and it wins and plays a small diamond and the diamond queen and Ace collide for all the matchpoints.

Tom again in matchpoints playing for the all important overtrick.

♠ J10xxx ♥ A ♦ xx ♣ AQ987

♠ AQxxxx ♥ Kxx ♦ x ♣ Jxx I opened a club and Tom responded a spade and LHO

pre-empted 3♦ . We got to 4♠ and LHO led a diamond to the Ace and returned a spade. Tom looked at it suspiciously and went up with the Ace . LHO obliged with the King . Now how do you play the clubs for all the matchpoints ? DNA analysis is always appropriate when the opponents have pre-empted. They have given you information about a 7 card suit. So lets give LHO 7 diamonds and he has shown up with 1 spade. Lets continue with the analysis by playing hearts first. You go to the heart Ace and ruff a diamond. You cash the heart king and discard a club. You ruff a heart and LHO follows and you return to your hand with a trump. The DNA analysis has uncovered 1-3-7-? LHO can not hold more than two clubs . To make the rest of the tricks you must play for a doubleton club king on side which was the case. You play small and insert the queen and play the club Ace dropping the King for +680 and a top. DNA scientist or Bridge player ? The gap is decreasing .