31st European Bridge Championships 1974, Herzlia
The following deal from the France-Austria match is a good exercise:
Dealer: North Vul: E/O
| West | East |
 K 5 7 6 A J 10 3 A K Q 7 4 |
A J 10 9 2 A 9 5 K Q 9 4 3 |
| Buchmeier | InDerMaur |
| 1 |
|
| 2 |
3 |
| 4NT | 5 |
| 5NT | 6 |
| 7 |
The End |
South leads: 8
What trump should the declarer play to make seven diamonds?
The only danger lies in a 5-0 trump break. If North is void, as happens to be the case, there is still a chance.
Declarer must be able to cash three club tricks, for heart discards, the heart ace, two top spades, a heart ruff and wind up with a high cross ruff.
Therefore, it is essential for South to have at least three clubs and at least a doubleton in both major suits. Declarer must take his heart ruff with the diamond four, so the three must be played from dummy at the first trick, preserving the ace-jack-ten.
If East makes the slight error of winning the first trick with the diamond ten, he could be defeated if South has no more than a doubleton spade. South can ruff spades at every opportunity, and eventually the dummy cannot overruff.
As it happened, South had only a doubleton club, and the grand slam was unmakeable on any line. (His hand was: 8 7 K 10 4 2 8 7 6 5 2 8 2.)
In the other room, the French pair Leenhardt-Vial rested conservatively in six diamonds, just making.