Source: ACBL 2007 Bulletins You can read Part I, II and…Clicking Here
Spot cards often have a role in the play that is not obvious during the bidding.
South reaches 6
after trying for a grand. The 2 bid by West was Michaels, showing 5-5 in the majors. North’s 2
, showed a limit raise or better for diamond. (If North had a good hand with clubs, he would have bid 2
, 3 would have been a non forcing raise.) South asked for aces and then asked for kings. North denied a king and South chose to sign off in 6. Given the evidence, 7 was still possible if North had good clubs but South chose to give up on it. As it was, even 6 was not cold. West led the K. South won with the ace and drew the one outstanding trump. East had it.
Here are two questions:
1. If there had been no bidding, what are South’s chances of making 6?
2. Given that South learned something from the bidding, what are the chances of making 6 ?
The answers:
With no bidding, 6 is 50% . Quibblers might say it is better than that, but it is fair to say 50% is close enough. With the actual bidding, however, 6 is closer to 80%.
How should South continue after drawing the trump? Hint: The correct line is the same, regardless of whether the opponents bid.
One possible line is to ruff out the spades, cash the 
A K, and give West a heart trick. If he has no more clubs, he will have to give South a sluff and a ruff. The problem is that West may have a club to cash or that East can win with the J, which will allow him to cash the setting club trick.
The key to making this contract is to appreciate the spade spots in dummy. Take over as declarer and try this: lead the Q. If West plays low, finesse. If West covers, win the ace and lead the 10 ! If East plays the jack, you ruff and discard a loser on the 9. If East does not cover, discard your heart. West can win, but the 9 is now good for a club discard.
Basically, the slam is cold if West has the K. With no bidding, West is about 50% to have it, but with the actual bidding, he is even more likely to have it.
The complete deal: 
North probably looked more fondly at his Q than he did at his 9 and 10. Little did he know …