An intra-esting finesse

Nowadays the most popular site for online bridge is BBO (Bridge Base Online), which offers free bridge any time you choose to log on. Today’s hand, submitted by Nick Hughes, was played on BBO.

Dealer South, Nil vul. Contract: 4H by South. Lead: DJ.

NORTH
 A852
 QT3
 854
 J83

SOUTH
 K93
 AKJ76
 AK7
 95

WEST  NORTH  EAST   SOUTH
                    1H       
Pass  2H     Pass   4H
All pass

A straightforward auction saw North-South reach a marginal game contract. West led the jack of diamonds. How do you plan the hand as declarer in 4H?

There are two losers in clubs and a deep loser in diamonds and another in spades. The clubs are ready to be lost off the top as soon as the opponents get the lead and play clubs, but you have a bit of time to try to do something with one of the other losers.

Declarer came up with a plan, drawing trumps then ducking a spade. If the suit divided 3-3 the fourth round would come good to provide a parking place for (say) the diamond loser. However the odds of a 3-3 break are only 36% and this time spades were divided 4-2 (48% chance).

There are many different finessing card combinations encountered at the bridge table. Success on this hand required an understanding of a radically different type of finesse called the “intra-finesse”, where the first finesse does not expect to create an extra trick but rather to set the stage to pin a big card on the next round. Let’s see how it works.

Draw trumps in three rounds, finishing in dummy. Next lead a spade and (if second player plays low, in this case the S6) insert the S9, the so-called intra-finesse. This loses to the S10.

Say that West persists with diamonds. You win and might play hearts just to force enemy discards but then you cash the SK and see the SJ drop from East.

You do not know the spade layout for sure. There are two relevant holdings possible in spades. East may have started with the Q-J-6 but is more likely to have started with J-6. With Q-J-6, East may have split honours on the first round of spades, and also could have thrown the queen instead of jack on the second round (the principle of restricted choice – with only J-6, East has no choice as to which honour to play on the second round).

Going with the odds, you assume East started with J-6 and now has no more spades, so you lead your S3 to finesse to the S8, which wins, giving you the extra trick needed for the contract. The full hand was:

          NORTH
          ♠ A852
           QT3
          
 854
           J83
WEST                EAST
♠ QT74              ♠ J6
 85                 942
 JT6                Q932
 AQ72               KT64
          SOUTH
          ♠ K93
           AKJ76
          
 AK7
           95

Note that West could have thrown declarer off the scent by winning the first round of spades with the queen. Declarer would then have assumed that the S10 “must” be with East, and would therefore not have tried finessing to the S8 and would thus have been defeated. In real life, only a world class player (or a beginner) would find that odd play.