Playing OKB has been a big change for us. We were die-hard ACOLites, playing a weak NT, and 4-card H suit opener. We changed gradually, and we found that one of the nicest conventions around OKB is the Jac2NT response to 1-of-a-major. It is well designed, and if applied properly, it can yield you a bushel of points.
With a fit, responder can   tell   declarer about his hand with the use of the SPLINTER, and the DELAYED GAME RAISE. The JACOBY 2NT was designed so that responder can   ask   declarer more about   his   hand. Of course, it is forcing to game.
Take this hand, for instance :
J 10 5 3
A 10 5 3
§ 10 7 3
K 7 6 4 2
K 8 6 4
§ A 8 6
ª K 9 6 4
A Q 9 8 3
§ K Q 5
ª Q 8 7 2
Q J 9 7
§ J 9 4 2
(Board rotated for convenience)
- 2NT is the Jacoby 2NT convention. Responses are:
- Bid a new suit at the 4-level showing a second 5-carder; failing that,
- Bid a new suit at the 3-level showing a singleton or void in that suit; failing that,
- Bid 3 of your suit with 18-20 points; failing that,
- Bid 3NT with 15-17 count; failing that,
- Bid 4 of your suit showing a 12-14 hand.
- Response of 3 shows a shortage in diamonds.
This, of course, helps Sarb greatly in assessing his hand.
- 4NT was RKCB, hearts being agreed implicitly with the 2NT bid.
- 1 or 4 controls. The heart queen is not investigated as there is a 5-5 fit in hearts.
The play was routine. After the lead of the diamond ace, the opps accepted the claim of 12 tricks.
This gave us 72.03%.