You should refuse to win the first spade; partner follows suit, which is exciting news. Assuming declarer plays a second spade, you should duck this trick as well. When a third spade is played, the time to win the ♠A has arrived at last, and you should win the trick. You now play your last diamond; declarer does not have any more trumps in his hand, and is forced to ruff in dummy, thereby establishing your low trump as the setting trick. If declarer does not play a third round of spade and starts cashing winners instead, you will eventually ruff a club to score the setting trick. This technique of forcing the opposition to ruff in order to promote your long trump has been appropriately named as the forcing game.

Next week's deal contains an advanced application of the forcing game. If you had not seen the forcing game before, this week's deal was intended to prepare you for next week.

Analysis:
Bridge Baron's double dummy solver confirms that starting out with three rounds of diamonds, followed by the forcing game described in the solution, is required to defeat the contract.

Bridge Baron's Line of Play
Bridge Baron made no mistakes on this deal, executing the forcing game to perfection. Bridge Baron started out with three top diamonds, and when declarer led trumps, Bridge Baron ducked the first two rounds, won the third round and forced dummy with a fourth round of diamond.
Par Contract Analysis:
The par contract on this deal is 3♠ by North-South, though it is difficult to imagine them stopping short of game.

Bridge Baron deal No : N4563-04425-47188-29841-50212-42092