This challenging deal is from the third round of the Northern Bridge league.
Many pairs played in six hearts, but were unable to cope with the four one diamond break, though the contract can be made by taking the club finesse after drawing trumps and then conceding a spade.
The above auction reached the winning spot. West decided that it was quite likely that one red suit or the other would not be breaking as South seemed to be bidding on minimal values. He thought he could probably cope with a bad break in one suit as any spade or club finesses would likely be working.
On a spade lead South played the king which meant the contract could be made if either, but not both, red suit broke 4-1. If hearts prove to be 4-1 West must duck a diamond. In practice West ran the hearts followed by the ace and king of diamonds to squeeze South in the black suits for an overtrick. If South had played the eight of spades on the first round West makes the contract with the aid of the club finesse.
On a diamond lead West can at some point take the club finesse and set up an extra trick in spades.