Trade a risky loser for a safe loser
Charles Maurice de Talleyrand-Perigord, a prime minister of France in 1814 and `15, said, “The art of statesmanship is to foresee the inevitable and to expedite its occurrence.”
The art of bridge declarership is to foresee the inevitable losers and to ensure that none occur unnecessarily.
In today's deal, South is in four hearts. West leads the diamond ace: two, 10, jack. West cashes the diamond queen: nine, three, four. West, trusting his partner's high-low signal, continues with the diamond king. What should declarer do?
After North raised to two hearts (which would have been correct even if West, with a different hand, had passed), South's jump to game was a slight overbid, but the vulnerable game bonus was an irresistible lure.
South starts with four losers (three diamonds and one club). His first thought will be a diamond ruff on the board, giving 10 tricks via two spades, five hearts, two clubs and that ruff. However, if East is being honest, he is ready to overruff the dummy at trick three. Then, unless the spades are 3-3, there will be an inevitable club loser. South should make a loser-on-loser play, discarding one of dummy's low clubs instead of ruffing.
West will probably shift to the club queen. Then the simple route for declarer is to win with dummy's king (now the honor from the shorter side first), draw two rounds of trumps, cash the club ace and ruff his last club on the board. This isn't guaranteed to work, but probably will.
Always consider a loser-on-loser play when an overruff is threatened.