Declarer cashes a master card in a suit, thereby promoting an opponent’s card to top rank. He then proceeds to execute a squeeze play and the opponent’s apparent winner does not materialise. This process is known as the «Vienna Coup.» Most players have heard of this operation but a request for the whys and wherefores usually leads to some embarrassment to let us try to get to the root of the matter.
One type of menace is always involved, the simplest example being ace and at least one small card in one hand and queen and a small card in the other. The jack or even a lower card will serve instead of the queen provided one opponent only holds the intermediate cards. Examine this situation:
| South | North |
 J (squezze card)  J 3 |
K A 2 |
West holds the ace of hearts and king-queen of diamonds and cannot take a trick: but if East holds these Cards declarer must discard in dummy first. If he parts with the king of hearts the heart menace is gone and if he discard, the two of diamonds the diamond suit is blocked. Declarer can do nothing about it in this situacion as the diamonds are needed to act as a two-card menace opposite the squeeze card. But take the following position:
| South | North |
| J (squezze card) 2 J 3 |
A J A 2 |
If West holds king and queen of hearts and king and queen of diamonds he is truly squeezed, but if East holds these cards dummy must either shed the jack of hearts, thus destroying the heart menace, or discard the two of diamonds which removes the entry card to the jack of diamonds should it become established. Declarer could have done something about it on this occasion. If he had taken the precaution of cashing the ace of diamonds (Vienna Coup) in the earlier play while still had entry to the South hand in order to play the squeeze card the following ending would have been reached:
| South | North |
| J (squezze card) 2 J |
A J 2 |
This is a normal simple squezze ending with the menaces divided between the two hands, which will squeeze either opponent with the only guards against the two menaces. A Vienna Coup, therefore, is an unblocking play which will permit declarer to have menaces in both hands and therefore squeeze either opponents. When planning a squeeze play which you wish to operate against either opponent always ask yourself the following questions—
(a) Have I a menace containing a master card in one hand and an established card in the same suit in the other?
(b) Have I another menace which will meet the condition «at least a two-card menace, or two cards forming part of a split menace, opposite the squeeze card?
If you have both, a Vienna Coup always be brought off by cashing the master card referred to in the first query while you still have entry to the hand with the squeeze card.
Consider this hand:
| Q 8 7 A Q 6 5 7 6 5 A K 10 |
||
| 2 9 7 3 2 Q J 9 8 7 6 5 4 |
9 6 5 K 10 8 A K 10 Q J 9 8 |
|
| A K J 10 4 3 J 4 4 3 2 3 2 |
East made an informatory double of North’s one-heart opening but South reach a contract of four spades. West led the queen of diamonds and after taking three diamond tricks East led the queen of clubs, on on the table. In view of East’s informatory double South placed the king of hearts with East and considered a squeeze. The squeeze card will obviously be a– trump and it is noted that the clubs provide two-card menace opposite the squeeze card. To squeeze East, South requires a menace behind him and the jack of hearts serves that purpose. Declarer therefore cashed the ace of hearts and ran down the trumps discarding hearts and reached this situation:
| Q A 10 |
||
| inmaterial |
K J 9 |
|
| 3 J 3 |
South played the three of spades, discarding the queen of hearts from dummy and East found the pressure too great.