CHAPTER 1- THE 2/1 STRUCTURE

There are lots of variations to 2/1, and the OKbridge card should not be considered a universal standard. In all 2/1 systems, however, the general principle is the same- any new suit bid by responder at the two-level is a game-force.

For example:

1S : 2C Gameforcing. Neither player can pass until a game of some sort is bid. In the OKbridge system, there are no exceptions.
1NT : 2NT Not a gameforce. The two-level response must be in a new suit.
1S : 2S Not a gameforce. Again, the two-level response must be in a new suit.
1C : 2D This is a strong jump shift and is, of course, gameforcing.

Opener's Rebids

Simple rebid: The catchall bid, does not promise extra strength
Jump rebid : Solid 6-card suit or better
New suit at the 2-level : Natural, at least four cards, any strength
New suit at the 3-level : Splinter in support of responder
2NT : 12-14 balanced (no 3-card support)
3NT : 18-19 balanced (no 3-card support)
Single raise : At least 3-card support, any strength

2/1 and strong jump shifts are OFF in competition BETWEEN opener and responder.
For example:

1S - 2C - 2D 2D shows 10+ points and is not gameforcing. The interference is in front of responder.
1S - P - 2C - 2D 2C is still gameforcing. The interference is behind responder.
1C - 1D - 2H 2H is a weak jump shift- 6 card suit, 0-6 points. This is signoff bid and is, of course, NOT gameforcing.
1C - P - 2H - 3S 2H is a strong jump shift, great 5-card suit or better, 17-19 points. The partnership is still in a gameforcing auction (unless they want to defend 3S-X).

CHAPTER 2..................................MAJOR-SUIT CONVENTIONS
CHAPTER 3..................................1NT CONVENTIONS
CHAPTER 4..................................DOUBLES
CHAPTER 5..................................MISCELLANEOUS
CONTENT..................................CONTENT OF OKBRIDGE 1/2 SYSTEM