(1) - New Minor Forcing
(2) - RKC Blackwood in Spades
(3) - 2 key-cards without the trump queen

West leads a club against your excellent slam. You win the Ace, and play a spade to your Ace, West follows with the Jack. How should you continue?

Solution:
You should guess spades first, and if you guess wrong, the contract can still be made on a winning heart finesse. Having come up with a general scheme, the question now is how do you play the spade suit. Here are the two lines of play you should consider:

Line 1: Cash the ♠K. If West shows out, enter dummy with the ♦A, and take a heart finesse.
Line 2: Enter dummy with the ♦A, and run the ♠10 (or ♠9). If it loses to the Queen, then you can enter dummy with a spade, and take a heart finesse. So, which line should you take?

It looks as though this is 50% guess. It might also seem right to follow line 1 and play for the drop, since this is a variation of the "eight ever nine never" rule. Surprisingly, the correct play is to play West for the singleton ♠J, and finesse the second round of spades! This play follows a rule called the principle of restricted choice. According to this principle, holding QJ doubleton of spades, West had a choice of playing the Queen or the Jack, and might have very well chosen to play the other honor. On the other hand, holding a singleton honor, West was forced to play the card. In the former scenario, West's choice of plays was unrestricted, while in the latter case, West's choice was restricted (hence the name). The odds of finessing as opposed to playing for the drop are almost 2 to 1. Line 2 is therefore the better play.

Analysis:
A double dummy analysis is not appropriate for this deal, as this is a single dummy problem (looking at all four hands would hence make the problem trivial).
Par Contract Analysis:
6NT is the par contract on this deal. However, a winning spade guess is required in 6NT. 6♠ is a superior contract as even on a wrong spade guess, the heart finesse offers the contract a chance.

Bridge Baron deal No : 22168967416009583628971776783