Simple Finesse

A simple finesse is a finesse for a card (usually an honor) held by the opposition:

		Dummy
		AQ87
West				East
K64				32
		South
		JT95

In this layout, imagine that South is on lead and needs all 4 spade tricks. The proper approach is to lead the J. If West does not cover, then dummy plays low and South repeats the process by leading the T.

The a priori chance for a simple finesse is 50%, since it is a 50-50 likelihood whether either defender holds the missing honor.

It is sometimes critical to lead the correct card for a finesse. Imagine that the above distribution is changed slightly:

		Dummy
		AQ97
West				East
KT				8432
		South
		J65

This time South must lead low to dummy's queen. On the lucky lie of the cards, South will win all 4 tricks. If South makes the mistake of leading the J, West will cover with the K. South can win the A, but must eventually concede a trick to East's 8.

It is always better to finesse for a king than to "play for the drop", except when holding a combined 11 cards in a suit. In that case, the odds are 52.29% in favor of playing the ace as opposed to 50% for the simple finesse. ¹

		Dummy
		AQJT5
West				East
???				???
		South
		987632

South leads a heart from hand and West plays the 4. Without any other information to go on, it's slightly better to play dummy's ace and hope to catch East with the singleton king.

When holding a suit combination headed by the AKJ, it's best to finesse when holding 8 cards or less in the suit. If holding 9 or more cards, then it's best to play for the drop. This is where the phrase "Eight Ever, Nine Never" comes from.

		Dummy
		AKT95
West				East
???				???
		South
		J432

In the above 9-card combination, South should play dummy's top diamond honors. Statistically speaking, playing for the drop is a 52% chance of success, whereas the simple finesse is only 50%. ²

In an 8-card combination, it's usually best to cash a top honor before finessing for the queen:

		Dummy
		KT875
West				East
???				???
		South
		AJ9

If South decides to play West for the queen, the right approach is to cash the A, then lead the jack.

However, there is one tricky 8-card combination that should be appreciated:

		Dummy
		AKJT92
West				East
???				???
		South
		54

Before finessing, it may look right to cash the A to try dropping a singleton queen. But the odds actually favor taking the immediate finesse. If West has Q-x-x-x, then it is necessary to take two finesses through him. This is more likely than East turning up with the stiff queen.

When holding a suit combination headed by the AKQT, it's best to finesse when holding 6 or fewer cards in the suit. In the layout below, declarer's best hope is to cash the ace of clubs and then lead low for a finesse of the jack.

		Dummy
		KQT9
West				East
???				???
		South
		A4

If holding 7 or more cards in the suit, then it becomes statistically better to play for the drop:

		Dummy
		AKQT9
West				East
???				???
		South
		54

Depending on declarer's suit split (4-3, 5-2, 6-1), the odds of success range from 52% to 61%. ³

¹ How to Calculate Bridge Suit Split Combinatorics/Probability by Durango Bill.

², ³ Francis, Henry (2001). The Official Encyclopedia of Bridge, 6th Edition.