Mental bridge exercises are good for your mind and even better for building partner’s esteem..  They make you think hard (which of course is what you are supposed to do playing bridge).   Here’s an example, and an easy one at that.  You are North and the bidding so far is:

 

SOUTH               NORTH
1 D                         1 H
1 S   
                    
Partner (South) bid twice.  Typically that’s about all of the information you get before deciding on a contract.  Before you make a final decision, you need to glean everything you can from these two bids.

As to strength, you know South has 13 points to open.  She did not jump at the second round, so it is reasonable to judge that her hand is limited to a range of 13 to 15 or perhaps at the most 16 points.

What about distribution?  A diamond opener - at least four diamonds, maybe more.  The second bid tells all, more or less: not enough diamonds to rebid them; not enough hearts to raise; exactly four spades.  I give South four spades, two hearts, four diamonds and three clubs (4-2-4-3).  What do you think?

Ok so I might be wrong; South might have three hearts, but that is less likely and probably won’t make any difference.  Also South could have five diamonds instead of four (4-2-5-2), and that might make a difference if you are interested in diamonds.  Personally I am hardly ever interested in the minors which is why I assume South has only four diamonds.

Now having figured out partner’s hand, what would you bid next holding these tickets:

NORTH

S) 6
H) K 5 4 3
D) Q J 10 3 2
C) A Q 2

This hand is quite good - 12 high-card points opposite an opener; great diamond support but no help in spades.  However with a 5-4 or 5-5 diamond fit and the spade singleton, the hand is worth game so the normal thing to do is go for a five-diamond contract.  On the other hand, I like to play notrump, and I also like nine-trick games in preference to eleven-trick games.  Since we have all suits covered, I prefer 3 NT.