Negative Doubles (Sputnik) 

Sputnik is a double convention. When the 1st opponent overcalls a minor openning with 1 Spade, Responder's double shows at least 4 cards of Hearts and no Spade stopper with 7+ points, and he does not have any natural response.  Either Responder has 4 cards of Hearts so he can not bid at the 2nd level or he has 5 cards of Hearts with less than 11 points. This application may differ according to bidding systems. For instance some players utilize the double to 1 Heart overcall to show 4 cards of Spades. There may be various sputnik applications, so following table summarizes our suggestions.

Opener	1.Opponent	Responder	Explanation
1 Club	1 Spade	Double	At least 4 cards of Hearts, 7+ points, no Spade stopper
1 Club	1 Heart	Double	At least 5 cards of Diamonds, 7+ points, no Spade stopper
1 Club	1 Diamond	Double	No Diamond stopper, no 4 cards of major, no support, 7+ points
1 Diamond	2 Clubs	Double	At least 4 cards of Spades, 4 cards of Hearts

In some systems, double to 1 Diamond overcall is used to show 4-4 major distribution. This version is meaningless because natural bidding is possible in the 1st level.

The application in the last row in the above table could be utilized for the other overcalls at the 2nd level. For instance double to 2 Diamonds overcall over 1 major openning will show the other major and Clubs. In this application the other two suits may not be necessarily 4 cards, but there may be some other distributions with a good hand.

The 4th Player (2nd opponents) may also apply Sputnik convention. These are known as Responsive Doubles. Let's give two Responsive double application in the following table.

Opener	1.Opponent	Responder	2.Opponent	Explanation
1 Diamond	Double	2 Diamonds	Double	7+ points, 3 suited hand, no 5 cards suit
1 Diamond	1 Spade	2 Diamonds	Double	At least 5-4 distribution on the other 2 suits

Now a Sputnik example for the 1st Opponent. 

Opener	1.Opponent	Responder	2.Opponent	Opener	1.Opponent	Explanation
1 Club	1 Diamond	1 Heart	1 Spade	2 Hearts	Double	Good openning value, Good Diamonds, 2 cards of Spades

Opener may also apply Sputnik. 

Opener	Responder	2.Opponent	Opener	Explanation
1 Diamond	1 Heart	1 Spade	Double	No Spade stopper, no 2nd suit, 16+ points, 3 cards of Hearts