There is a situation that goes like this.
This is the trump suit, you play the Ace and you see the Jack drop with East, what next.
The real question is — do we play east for having singleton Jack or QJ doubleton. If it is a doubleton, we need to play the King next, if it is a singleton, we go for the finesse.
Let's take a step back
Let's take a step back and forget about this question for a moment.
Think of these three suit combinations.
1. ♠QJ
2. ♠Q
3. ♠J
Lets say we dealt the above suit combination 3,000 times. And each time, I gave east either the QJ, the Q or the J.
So, for 1,000 of the deals it is the ♠QJ
For 1,000 of the deals it is the ♠Q
For 1,000 of the deals it is the ♠J.
Are you with me so far?
Let's revisit the original problem.
Every time, with these 3,000 deals, when we play off our first card east will play either the ♠Q or ♠J.
Are you going to play for the finesse or for the drop?
I've already told you that 1,000 of them are a singleton ♠J and 1,000 are a singleton ♠Q, only 1,000 are doubleton ♠QJ.
2 out of 3 times it is a singleton, only 1/3 times is it the doubleton ♠QJ — so we play for the singleton.
In summary
When you have this suit combination or similar, where you are trying to decide if the player has a singleton honor, or doubleton honor, remember — just like in the 3,000 practice deals, there will be 2/3 times where the honor is singleton, and 1/3 where it is doubleton.
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