A maneuver devised by Eric Kokish to facilitate the bidding of very strong balanced hands. In this sequence:
Opener Responder
2♣ 2♦
2♥ 2♠
2♥ is semi-artificial, promising either hearts or a strong balanced hand. 2♠ is forced, and opener bids 2NT if he is balanced. Other rebids are natural, showing hearts. This is advantageous with the strong, balanced hands too strong for a non-forcing 2NT rebid because Stayman and transfers can be used conveniently at the three level. This device loses a little ground when the opener is unbalanced with hearts because responder loses the chance to use a second negative. One solution is to switch opener’s rebids of 3♣ and 3♥ at his third turn.
The convention can be enlarged by the following variations suggested by Danny Kleinman:
(1) After 2♥, responder bids 3♣ and 3♦ with a long minor and moderate values.
(2) After 2♥, responder bids 2NT with a 6-card spade suit, allowing opener to play spades. Similarly, 3♥ shows six spades and three hearts, with opener the declarer in either major.
SOURCE: "Conventions", The Official ACBL Encyclopedia of Bridge, 7th ed. Horn Lake: American Contract Bridge League, Inc., 2011, page 295. Print