CHAPTER 2- MAJOR-SUIT CONVENTIONS

1NT Forcing

As a result of the 2/1 response being a game-force, responder will often have a 10-12 point hand with which he would like to make a 2/1 bid but cannot; hence the 1NT Forcing convention. The 1NT response to 1H or 1S shows 6-12 and is a one-round force (since responder may have 12 points). Opener's rebids are as follows:

Any reverse : 16+, natural, forcing
Simple rebid : 12+, a good 6-card suit, nonforcing
Jump rebid : 19+, natural, forcing
Jump shift in a new suit: 19+, natural, forcing
2NT : 18-19, balanced, nonforcing

If opener's hand does not fit into these categories, he must bid his longest side suit up the line if possible. In each of the following cases, opener has bid 1S and heard 1NT forcing:

K Q J T 9
K J T 6
A 3
5 4
Opener must rebid 2H.

K Q J T 9
K J T
A 6 3
5 4
Opener must rebid 2D. (alertable)

A Q J T
K J T 9 8
Q 6
5 4
Yuck. Opener cannot reverse, so he must rebid 2C. (alertable)

Responder's rebids are as follows.
First, the weak (6-9) rebids:

Pass: If opener has rebid 2m, responder should try to have incredible 4-card support or better, since the side may be playing in a 4-2 fit.
New suit at the two-level: A five-card suit, signoff.
Two of opener's major : Responder may only have two-card support.
New suit at the 3-level : A very good 6-card suit, signoff.

Now, the strong (9-12) rebids:

2NT : Balanced, nonforcing
Three of opener's major : Invitational, normally 3-card support
Three of opener's minor : Natural, normally 5-card support
Jump to game : Natural

Example hands.
Opener has opened 1H, responder has bid 1NT forcing, and opener has rebid 2C:

K 4 3
9 8
K J 4 3
J 4 3 2
Correct to 2H. Don't pass!

K 4 3
K 9 8
A J
J 9 8 5 4
Invite with 3H.

T 4 3
K 8
Q J 2
K Q 8 7 6
Raise to 3C.

K J 3
A 8
Q J 3 2
T 9 8
Bid 2NT.

6
A 5 3
5 2
A Q T 8 7 6
You can try 4H now that a double-fit is apparent.

REVERSE DRURY

Based on the Drury convention invented by Douglas Drury, Reverse Drury is an effective way of gauging the strength of partner's third and fourth seat openers. When partner opens 1H or 1S in third or fourth seat, 2C by responder shows 10-12 points with at least three trumps. With a subminimum hand, opener bids 2M, telling responder to pass. With a normal opening bid, opener rebids 2D. The natural 2C response is lost, but many players consider this a marginal sacrifice. Thus

Opener
K Q J 4
K 8 5
T 9 8
7 6 2
Bidding
1S : 2C!
2S! : P
Responder
A 9 8 7
A 9 3
K 5 4 3
8 2

And

Opener
Q J T 4 3
A 8
K T 6 3
A 5
Bidding
1S : 2C!
2D! : 3D
4S : P
Responder
K 9 8 7
K 9 3
A J 9 5
3 2

Special Rebids by Opener:

K Q J 5 2
K 9 8 7
A 3
4 2
1)

K Q 9 8 7
5
A J T 3 2
A 9
2)

A J 5 4 2
8
K 9
A Q T 6 5
3)

In each case opener has bid 1S and received a 2C response.
In 1), Opener bids 2H to show 4+ hearts in case there is a 4-4 heart fit. He does not guarantee opening strength.
In 2), Opener bids 2D, planning on rebidding 3D. As he is committing the partnership to the three-level, this does show a full opener.
In 3), Opener bids 3C to show his club suit. Again, since he is taking the bidding to the three-level, opener does promise a full opener.

Weak Jump Shifts (in competition only)

A jump shift by responder in competition shows a 6-card suit and 0-6 points. For example:

1C - 1D - ?

K Q 7 4 3 2
4 3
3 2
T 9 8

Bid 2S.

Opener's rebids are:

Pass : On most hands, since responder only has 0-6 points.
2NT : Game try, forcing. Responder must rebid his suit to show a minimum.
Simple raise : Purely preemptive.
Double raise of a minor : Invitational.
Any new suit : Natural, nonforcing.

CHAPTER 1..................................THE 2/1 STRUCTURE
CHAPTER 3..................................1NT CONVENTIONS
CHAPTER 4..................................DOUBLES
CHAPTER 5..................................MISCELLANEOUS
CONTENT..................................CONTENT OF OKBRIDGE 1/2 SYSTEM