Sputnik
Also called Negative Doubles
This is a conventional reply to partner's opening bid followed by an intervening bid by the opponents. It promises length in the two unbid suits but denies enough count for a free bid at the level required (probably has 6 to 10 points). This bid is descriptive only and requires no special response from partner. Jump responses by opener are only invitational. To force another bid, he must cue bid.