Having opened 4 ♠, West leads the two of spades and East plays the queen. Do you think something fishy is going on?

For sure. East’s queen of spades is consistent with a holding headed by the queen, king-queen, or aceking-queen. The vulnerable West has opened at the four-level and so must surely have at least one of the top spade honours. Therefore West has underled (at least) his ace.

Why? Answer West is trying to put his partner on lead and his choice of the two of spades (a suit preference card asking for the lower-ranking suit) makes it clear he has a void club and is hoping for a ruff. West would hardly gamble the ace-underlead if he had a likely trump trick (for if there was a spade trick, there would be two defensive tricks: down one), so East rates to hold the king of trumps (which declarer must hope is singleton or doubleton).

Declarer now has enough clues: East has the king of trumps and clubs are not splitting. He should play to set up hearts and spurn the trump finesse. After ruffing the spade, at trick two he ruffs a low heart, then cashes the ace of trumps.

A disgruntled East’s king of trumps falls. Declarer ruffs the second spade, ruffs a second heart, both following to reveal the 3-2 split, then plays queen and a third trump to West.

Declarer ruffs West’s spade return, crosses to his ace of clubs, cashes the ace of hearts felling East’s king and the suit is good. 12 tricks and slam made.

Note that failure to ruff a heart at trick two would not be fatal. Say declarer instead leads a trump to the ace at trick two. East’s king is felled and he now ruffs the second spade with his last trump, ruffs a heart and plays queen of trumps and a third trump to West. He ruffs West’s spade return and cashes the last trump to squeeze East in hearts and clubs (try it).