Dubious Logic

The Dummy Reversal

Even experienced players approach the grand slam zone with care. The caution comes from the rarity of the situation and, it would be dishonest not to admit it, trying to see past the undeniable thrill of bidding to the seven level. But the most pertinent consideration is that considerable surety is required for such an adventure. In teams play it is galling to discover that almost all the benefit could have been realised by landing the small slam as opponents were only in game. These considerations put the required chances for success up very high, about 70% is thought appropriate.

At matchpoint pairs it should be no lower, if you stop in six and play the cards well, you'll get a good score anyway. This hand from the Ipswich and Kesgrave Swiss Pairs is a case in point:

Initially I received this as a bidding problem. Over the telephone, rather than at the table, it was easy to bid optimistically and I urged advancing to seven when the degree of fit and control was discovered. West had started with a spade, though incidentally my preference for above minimum black five-five hands is to begin one club, and North overcalled in hearts. When the East cards were revealed I was left wondering how I would have fared in 7♠. North naturally enough starts with the ace of hearts and you ruff, take a moment to settle upon a line of play.

You can be sure that trumps won't be 2-2. If they were you would have at least one good plan; draw trumps in two rounds and throw two of dummy's diamonds on top clubs, ruff the clubs good (assuming they're 4-3), and you still have a trump left in dummy with which to ruff West's losing diamond. If trumps are not 2-2 however, you're unlikely to be able to execute this play so you should have 'plan B'.

Scoring seven spade tricks is a sound idea but rather than hope to score five in the longer trump hand and two in the shorter, you can achieve the same total by making three ruffs in the five spade hand to go with four in the other. This play is known, somewhat confusingly, as a dummy reversal – it doesn't matter which hand actually is dummy, it's the process of shortening the longer hand with ruffs, rather than the more usual other way around. Lets see how that works here. We take one ruff on the lead, then spade ace, low to spade queen (North shows up with 10xx), ruff a second heart, over to club ace, ruff a third heart with the spade king. Now lead a low club and ruff in dummy. As North has the last trump this is perfectly safe and we have reached:

Now there is an unexpected bonus to our careful play with trumps. When we draw the last one, throwing a diamond from dummy, if South has long clubs, he too will have to come down to a doubleton diamond. When we cross to West and cash the top clubs, we will throw a diamond and a heart from East. North has to keep the heart king so he too will only be able to hold two diamonds.

So even if South has five or six clubs (it surely can't be North with long hearts too) you will make this contract – the chances are excellent, maybe 95% or more. Was it worth bidding seven then? Almost certainly not. Those pairs who bid 6♠ and made twelve tricks were rewarded with 31 out 36 match-points – the risk of getting no matchpoints was not worth it.

Published Saturday 25.Sep.2004