Don’t let partner go wrong

West led ♦ 2, clearly a singleton from East’s perspective (why else would he lead dummy’s bid suit?). So, after winning ♦ A, East returned ♦ 9. When leading a suit for partner to trump, the Suit Preference Signal is used - a high card asks for partner to return the higher ranking of the other suits. West therefore knew his partner held ♠ A (♦ 9 was clearly East’s highest remaining ♦). He trumped ♦ 9 and returned ♠ 2. East won ♠ A and paused to reflect. Normally the lead of a low spot card (such as ♠ 2) asks partner to return that suit but East fell for the temptation to lead another ♦ in the hope West could trump again. Disaster! West had no more trumps so declarer could win ♦ Q, draw East’s trumps and discard his second ♠ on a minor suit winner in dummy. Whose fault?
Perhaps East should have respected West’s ♠ 2 lead which theoretically asked for the ♠ return, but West, alone, knew that the correct defence was to cash two rounds of ♠s. He should switch to ♠ K! He retains the lead to play a second ♠ to East’s ♠ A and down goes the contract!

ANDREW’S TIP: If you know how to defeat a contract, do not give partner the chance to do the wrong thing.