Zia

Zia's instinct was right

ª A 9 7 5 2

¨ J 9 3

§ A J 9

ª - ª 4 3

¨ 7 6 4 2 ¨ Q 10 8

§ Q 7 2 § 10 8 5

ª K Q J 10 8 6

¨ A K 5

§ K 6 4 3

This deal was played by Zia Mahmood in 7ª needing a good result to win a match. He won the heart lead, drew trumps and finessed §J succeeding when the clubs broke 3-3 with the finesse right.

He subsequently claimed that he had misplayed the hand and should have finessed §9, succeeding whenever West holds §Q and §10, approximately a 24% chance (actually 28.3%) whereas the finesse of §J and 3-3 break was only 18%.

I beg to differ! As long as the §J finesse works he will make the contract as long as the player who holds ¨Q holds at least three clubs. He also succeeds if ¨Q drops.

To see what would have happened if the clubs were 4-2 let’s transfer §2 to East and ©3 to West.

Declarer ruffs the lead, draws two trumps ending in dummy (keeping ªA for later), ruffs another heart, finesses §J successfully (West has §Q 7), cashes ¨A K (claiming if ¨Q drops) and cashes a top spade in hand and crosses to dummy with his last spade. He would have reached this ending:

ª 7

¨ J

§ A 9

ª - ª --

¨ 7 6 ¨ Q

§ Q § 10 8 5

¨ 5

§ K 6 4

When ª7 is cashed East is squeezed and would have to give him the last trick.

He would therefore succeed if the club finesse worked AND

¨Q drops OR

Clubs are 3-3 OR

¨Q is in the same hand as the long clubs

That works out as 35.5% as opposed to 28.3% for the deep finesse.

At the table experts do not make these calculations in depth. I am good at mental arithmetic and can calculate roughly “at the table” so my calculation would have been about 28% (24 + 2x2 for the vacant spaces) and 33% (slightly over half of [32% plus 6% plus 25%]); it took me 15 minutes to make the precise calculation using software but Zia’s instinct led him the right way.