I'm not much of a gambler. My cousins would play dreidl (a Jewish gambling game using a top and betting with gold covered chocolate coins called gelt) at Hannukah. I would wait until we all got our starting gelt and then leave, happy to eat a few pieces of chocolate. 

People who really like casinos can go on and on about odds. "Oh, this machine has 99% payout, but this one is only 99.87%." Try and stop them. Those tiny odds don't seem like they should make much difference, but over the long run, every little bit matters. 

The same is true at bridge. We're not always going to make the winning play, but we want to make the play that will work as frequently as possible. See if you're playing the odds in this deal: 

Contract 4

	DUMMY 762 A1098 AQJ  932
Lead:  Q
	DECLARER (YOU) AK9543 J K9 K764

The auction: 

West	North	East	South
			1
Pass	1NT	Pass	2
Pass	3	Pass	4
All Pass

After opening 1, we have to decide what to rebid after a semi-forcing notrump. 2 will be a popular choice. My father loves to show his four-card suit ("Why tell partner about 6 total cards when you can tell them about 9?") and he reads this, so I'm showing 2. Either bid is acceptable; it's a style choice. Our partner jumps to 3, inviting game. We have 14 with mostly aces and kings which makes this worth accepting by bidding 4. 

The Play

You receive the Q lead. Trumps are 3-1 with West holding three. What is your plan?

Most players would probably draw two rounds or three rounds of trump, play three rounds of diamonds pitching a club, and then hope that the A is onside. They will make half the time. Can you do better?

Sure. We have one spade loser (a slightly unlucky day), no heart losers, no diamond losers, and three club losers. The club finesse, as we said before, is a fifty-fifty shot. Are there any better propositions out there?

We have a lot of spot cards in the heart suit. Most of the time we see ruffing finesses as AQJ10 opposite a singleton or void, but here we can actually take a double ruffing finesse. 

After winning the lead and cashing another spade, play the J to the ace and then run the 10 (throwing a club if East does not cover). This is likely to lose to West, but West can't attack your club suit.

West plays another trump and then a diamond. We win in dummy and run another heart. If East covers, we ruff. If East ducks, we discard a club.

Try following along with the diagram below: 

Vul:None Dlr: S	762 A1098 AQJ  932
QJ10 K742 1087 AQ5		8 Q653 65432 J108
	AK9543 J K9 K764

One club goes on the 10 (likely losing, making this a loser on loser play). Then the next club goes on another heart (if East doesn't cover). If East does cover the third heart, we ruff, cross over in diamonds (overtaking the K with the A), and then throw away one club on the diamond and one on the good heart. The end result: we lose one spade, one heart, and one club. 

This will work as long as East has at least one heart honor. That's 75% of the time. With this thoughtful play, we improved our odds from the 50% finesse.

Even on one deal, that difference is large. Over the course of a session, it is often the difference between success and failure.