This deal was from a second round Higson Cup knock out match.
East made a mildly conservative decision to pass two clubs in the above auction.
North led the ten of diamonds, South cashed two diamonds and played a third diamond so that North could ruff with the seven to force the club queen.
Declarer now decided to play on hearts, the third round being ruffed in dummy and overruffed by South.
South could now count West for a 1534 distribution and made the key play of cashing the spade ace before playing another diamond. West ruffed with the eight (he needed to ruff high and play two more trumps to make the contract at this point). North now overruffed with the jack of clubs and gave South a heart ruff to beat the contract by one.
If South does not cash the spade ace before playing the fourth diamond West can discard his spade while North trumps and a loser disappears.