Source: ACBL
Bridge is primarily a game of language and logic. Of course, judgment and empathy play large roles, as does luck, at least in the short term. These puzzles feature language and logic. The idea is to deduce a significant amount of information from the bidding and opening lead.
# 4. You are South.
West North East South
1
2
Dbl
Pass 2NT Pass ?
a) How many diamonds does North hold?
b) As South, you hold: 7 
108432 AK84 
J76. What’s your call?
# 5. You are East
North South
1NT
3NT Pass
Partner´s opening lead is 4.
North
Q3
West East (You)
4 K10852
Declarer plays dummy’s 3.
a. Can you locate the missing heart honors?
b. What do play to trick one?
# 6. You are South
North (Dummy) 963 875 K42 9862
South (You) AKJ872 J9 A6 754
East opens 1NT (15-17 high card points), you overcall 2, and all pass. West leads the J. You win your ace and cash a high spade, collecting the 4 and 5, cross to the K and lead a second spade. East follows with the 10.
a. What questions should you be asking?
h. Do you finesse or play for the drop?
Solution # 4;
a. North holds four or five diamonds. North has at most three hearts – no 3 response to your negative double. The greatest major suit length North can have is 4-3, and with 4-3-3-3 North usually opens 1.
b. Bid 3 non-forcing. In general, whenever you take partner out of a notrump partial into his first suit, it should be a correction of contract.
Solution #5;
a. South holds either A J, or J x but not A J. With A J declarer would have tried dummy’s queen at trick one. If declarer has no heart honors, he would also try the queen, hoping the lead was away from A-K.
b. Play the K, catering to declarer J x. If declarer holds both high hearts, it probably doesn’t matter which heart you play, unless it is a specific situation where the defense must prevent the Q from becoming a late entry .
Solution to # 6:
a. Find out if the opponents are using negative doubles at the two level. While you’re at it, see if they are playing lebensohl or a similar convention that allows them to compete at the three-level without forcing to game.
b. If they are using negative doubles, play for the drop. The reasoning: their side has 24 HCP, giving West at least 7. Why didn’t West compete? If he had a singleton spade, he would presumably double with four hearts or compete in a long minor. A spade holding of Q-x, however, would discourage competition. If they are using penalty double the decision is closer. West may have been prevented from competing if his distribution is 1-4-4-4. Because he would likely have bid with any other distribution and a singleton spade, the finesse still seems like the percentage play.