Against a notrump contract, the lead of the queen is from QJ10, QJ9, AQJ with or without extended length.

 Your opponents bid 1NT-3NT, and your partner leads the Q. Dummy puts down the 73. Which card would you normally play with each of the following holdings?

a) K 5
b) K 8 4 2
c) A 2
d) 10 2
e)  8 5 2
f) A 8 2

a) Play the king and, if it holds, continue the suit. The idea is to get your king out of the way so the defence can drive out the ace efficiently.

b) You like the lead and should signal encouragement as clearly as possible. Play the eight.

c) Declarer has the king but partner may be able to set up enough tricks if you win the ace and return the suit immediately.

d) Unblock the ten. Partner would lead low from a queen-jack holding that does not include the nine so credit him with at least QJ9x(+). Partner, who may hold QJ98(+), will usually want to know who holds the ten.

e) This holding is not great news for the defence. Play the deuce unless you cannot stand any normal switch. It is an important principle of defence that you may send a signal that misrepresents your holding if you can see that a true signal will achieve a poor result.

f) Unless you believe that declarer might hold the singleton king, play the eight, encouraging. If declarer has four cards in the suit it will usually be best to have him win his king. Then you can win the second trick for your side to lead the third round through declarer. This might be the full layout:

             North
             7 3
West                      East
  Q J 9 4                    A 8 2

 
            South
              K 10 6 5

 If you win the ace and return the eight, declarer covers with the ten and remains with K 6 while West, on play, holds 94 and cannot continue the suit. If you withhold your ace, declarer can take his king or not but the defence can continue the suit fluidly in either case.