Deal 4
 
  4
♠ J 6 4
Q 8
K 9 7 3
♣ K Q J 10
 
 WEST  NORTH  EAST  SOUTH
1
pass2♣pass2
pass4passpass
pass

The bidding has been as shown.
Partner led the ♠3, dummy played the ♠4 and it is your play.

When you have made your choice click NEXT .
♠ 3


♠ K 10 2
6 4 3
Q J 10 6
♣ A 6 5
 


 

 
Deal 4
 
  4
♠ J 6 4
Q 8
K 9 7 3
♣ K Q J 10
  Play the ♠10.

Partner's low ♠ lead tells you that he has an honor in the suit.
There are only two ♠ honors you can't see, and you know he wouldn't underlead an Ace at a suit contract.
So partner holds the ♠Q.

You can see clearly what would happen if you played Third-hand-high and put on your ♠K.
Declarer would win his ♠A and could then set up a second ♠ trick by leading toward dummy's ♠J.

By playing the ♠10 you force declarer to win with the ♠A if he wants the trick.
But however he plays he can only make one ♠ trick when you play correctly.

For your side, 2 ♠ tricks and the two minor Aces spell defeat.

 Deal 5 
♠ Q 8 7 3
10 5
A 5 4 2
♣ 8 4 2
♠ K 10 2
6 4 3
Q J 10 6
♣ A 6 5
  ♠ A 9 5
A K J 9 7 2
8
♣ 9 7 3