A normal trump fit consists of a combined holding of at least eight trumps in declarers hand and dummy. But it is well known that lesser holdings sometimes produce an excellent contract. This is especially true of the four-three trump fit, known as a Moysian fit a tribute to the late Alphonse Sonny Moyse who wrote extensive articles on the subject.
West led the K and declarer quickly took advantage of dummys singleton: A; spade ruff (with heart ace); heart to nine; spade ruff; diamond to king. The remaining trumps were drawn; but when the diamond finesse failed, declarer went down one. He still fared better than he might have at three notrump (likely down two), but he should have succeeded.
Moysian fits are delicate contracts. With only a slight superiority in trumps declarer must time the play carefully to keep things under control. After winning the A, declarer should immediately lead a low diamond to dummys jack if the finesse wins, great; but if it loses, there is no damaging return. East wins the Q and might as well return a diamond (nothing matters). Declarer wins the K, ruffs a spade with dummys A, draws four rounds of trumps (throwing clubs from dummy), then runs the diamonds for his contract.
© 1997 Richard Pavlicek