This deal is from a duplicate at Bramhall and Cheadle Hulme.
South decided to upgrade his 22 count with a good five card suit and excellent controls to a two club opener.
Ostensibly this slam is on picking up the trumps for no loser, so needing either trumps break 2-2 or a singleton queen, plus there are good chances if East has all the trumps, which all comes to about 57%.
West led the jack of clubs and East ruffed. The slam was not so good now. However, East did not know which suit to play next, she guessed a spade.
Clearly East did not have the ace of diamonds or she would have cashed it.
Declarer won the spade return, drew trumps and ran all the spade and heart winners, at trick nine West was squeezed out of his club guard for a rather fortunate recovery for declarer.