Accidentally on purpose

It is usually easy to play perfectly when you see all 52 cards, but there are hands that are difficult to play correctly even when you have that advantage. For example, take this deal where West led the ace and another heart against six diamonds.

The slam would have been laydown had the trumps divided 2-1. But after declarer ruffed the second heart and West then showed out on the ace of diamonds, South had a difficult problem to solve. If he drew

East’s remaining trumps, he would not be able to ruff enough of his spade losers in dummy, while if he didn’t draw trump, East would overruff any attempt to ruff a spade.

Faced with this seemingly insuperable difficulty, South managed to make the slam anyway. Acting on the assumption that West’s distribution was almost surely 6-2-0-5, South drew two more rounds of trump and then led a spade to dummy’s ace, producing this position: