Two Over One (2/1) Game Forcing is a natural, 5-card major bidding system. When the auction begins 1D/H/S, a simple 2-level response in a new suit is forcing to game.

Responder promises 13+ points in the following 6 sequences:


Opener
1D

Responder
2C


Opener
1H

Responder
2C


Opener
1H

Responder
2D


Opener
1S

Responder
2C


Opener
1S

Responder
2D


Opener
1S

Responder
2H


Why Play 2/1?

2/1 offers the psychological reassurance that you'll never be accidentally dropped in a partscore. Have you ever made a "forcing" rebid with 17 points and watched partner pull out the Pass card? If so, you might know what I mean.

As for actual science, 2/1 saves bidding space by curtailing the need for strong jump bids by either player. This extra space can be used to bid games and slams more precisely.

Here's a Standard American auction that's undermined by a strong jump shift:

West
SAKQT65
H4
DA92
C863

East
SJ4
HAKT972
DQ85
CAK

West
1S
3S
Pass
East
3H
4S

East feels obligated to jump shift with a strong one-suiter. West, unfortunately, can do little but rebid spades. East then guesses to sign off, since West's spades could be as meager as SAxxxxx. A good-looking small slam is consequently missed.

Playing 2/1, however, the auction can be much crisper:

West
1S
3S
4D
5D2
6C4
Pass
East
2H
4C
4NT1
5NT3
6S

1 Roman Key Card Blackwood 1430
2 3 key cards
3 Asking for side kings
4 No side kings

East initially establishes a game force with 2H. West then jump shifts in spades - a special rebid in 2/1 that shows a strong running suit. (With weaker spades, he could simply rebid 2S.)

East then happily upgrades his spade holding and initiates a slam sequence.


Drawbacks of 2/1

The 1NT Forcing Convention

So invitational hands are excluded from 2/1 responses. What do you do with them?

When the auction begins with 1H or 1S, invitational hands get funneled into the 1NT Forcing convention, showing 6-12 points instead of the standard 6-10.

This creates some potential challenges:

  • 1NT Forcing may not adequately describe responder's shape
  • You can longer stop in 1NT when your side opens one of a major
  • 1NT Forcing may require opener to make some awkward rebids, especially with balanced shape

Bill Root and Richard Pavlicek once wrote that 1NT Forcing is like a carburetor that helps power a car. It's not pretty but does its job. Well, Audrey Grant's book "2 Over One Game Force" dedicates 45 pages to 1NT Forcing. Imagine buying a new car with an Owner's Manual containing 45 pages about carburetor maintenance.

Take a look at these problematic hands:

West
SKQT87
HK94
D53
CA72

East
SA
HAQJ83
D9742
CT64

West
1S
Pass
North
Pass
Pass
East
1NT
Pass
South
3D

East initially responds with 1NT Forcing because his hand is too weak for a 2H game-force. But 1NT masks East's heart suit, and the partnership misses its 8-card fit.

Another example:

West
SAK653
HK62
DQ74
C84

East
ST7
HQ9
D532
CKQJ52

West
1S
2D
Pass
East
1NT
2S

This time East bids 1NT Forcing with a lighter hand. West is stuck - he can't pass in case East has invitational values. Lacking a suitable rebid, West rebids his diamond fragment. The auction concludes in a less-than-ideal contract.


Partnership Agreements

The computer scientist Andrew Tanenbaum once quipped, "The nice thing about standards is that you have so many to choose from." This sentiment could easily be applied to 2/1. No two books about the system are exactly alike.

Some aspects of 2/1 that warrant partnership discussion:

  • Is a 2/1 response 100% game-forcing? What are the exceptions?
  • Do jump shift responses become weak or invitational?
  • Does opener promise extra values if he reverses over a 2/1 response?
  • What do opener's no-trump rebids mean?

An example of this last bullet:

S AJ3
H AQJ762
D 4
C K85

Partner
1S
3NT
You
2H
?

3NT normally shows a strong balanced hand in Standard American bidding. What does it promise if 2H is game-forcing, though? Some pairs treat it as 12-14 points, preferring to reserve the 2NT rebid for good hands that want to explore slam.

Memorization of such sequences can be taxing, especially given their infrequency. In short, thorough partnership conversations are necessary to make the most of 2/1.

See also

  • When Is the 2/1 Game-Force "Off"?
    Exceptions to the 2/1 "game-forcing" rule. This includes responses in competition and other possible agreements per experts like Mike Lawrence and Max Hardy.