Two Over One Game Force

Two Over One Game Force (2/1) is a system that allows you to slow the auction down on game-going hands. This makes for better slam bidding because neither partner needs to jump just to keep the auction alive. In fact, once the game force is established, the slower you go, the more powerful a hand you are showing.

When a person says they play 2/1, they are usually referring to not just the two main components, Two Over One and 1N Forcing, but also:

Many partnerships also include weak jump shifts, because the strong jump shifts are less needed if one can make a game-force at the two-level.

This chapter explains just the two main components. The other conventions are actually best learned first, so that you are comfortable with the other pieces before adding these last two ideas.

The two ideas, “Two Over One” and “1N Forcing”, are actually one big idea. Once in a while you’ll run into people who play “1N Forcing” by itself, but this doesn’t make much sense. Certainly, “Two Over One” without “1N Forcing” is impossible. So we treat the two ideas together.

When Are These Bids Forcing?

When we open a major in first or second seat, and the opponent passes, an unpassed responder’s bid of 1N is forcing one round, and the bids 2♣, 2♦, and 2♥ are game-forcing.

When we open one diamond in first or second seat, 2♣ is game-forcing. 1N is not forcing.

If responder is a passed hand, or there is any interference between the opener and the responder, standard bidding rules apply.

Interference after a 1N forcing bid takes opener “off the hook” and he may pass. An overcall after a game-forcing two-level bid does not cancel the game force.

“Game-forcing” means forcing to 3N or the 4 level. The partnership is not committed to five of a minor; if 3N is not biddable, we may stop in four of a minor. Once the game force is established, if one partner passes an interfering bid, the other must either double or bid on.

How Two Over One and 1N Forcing Combine

In standard bidding, a responder can raise an opening bid of 1♦, 1♥, or 1♠ to the two level with 10 or more points and a suitable suit. When responder is an unpassed hand, we are going to change that, so that these bids are game forcing, thus requiring around 13 points. This leaves a gap: what is responder to do with 10-12 HCP hands if he has no one-level response? He can no longer bid a suit at the two level.

The answer has to be separated into cases: bids over one of a major, and bids over one diamond.

  1. Over a major, the responder will bid 1♠ or 1N with such hands, forcing for one round. Most bids of 1N will still mean what they used to mean, a hand of 6 to a bad 10 points with no suitable one-level suit bid. However, some bids of 1N will be the stronger type of hand. It will be the responder’s second bid which shows which is the case. The opener acts as if the bid was 6-10 until proven otherwise, except that he cannot pass.

    The 1N response to a major can also be used when responder holds a 3-card limit raise. Responder will jump in the major on his next bid to show this. In this way, opener knows that a normal limit raise (whether 3M or using Bergen raises) is a four card raise.

  2. Over 1♦, lacking a major, but having limit raise values, the situation is simple: if responder has 4 or more diamonds, bid a limit raise in diamonds. (2♦!, the inverted minor limit raise, if playing that). Lacking that, responder has 4 or more clubs but lacks the values to force game with 2♣, so responder bids 2N. The 1N bid is used only for 6-10 point hands, and is not forcing.

The next two sections give the details on our two new bids.

1N Forcing

Since a two-level bid is now game forcing, any hand with 10-12 points that you would want to bid at the two level is a problem, since it is too strong for a standard 1N bid and too weak for a game-forcing bid. While most bids of 1N forcing are going to show the standard 1N bid hand, some will be the stronger type.

If partner opened a major and we have a four card raise, we will of course do that at an appropriate level.

When responder bids 1N, opener announces “forcing”.

Opener’s rebids after 1N Forcing

The opener has opened 1M and responder has responded 1N(forcing). Next, opener’s rebid is as follows.

  • Simple rebid shows 12-15, and a six card suit, not forcing.
  • Jump rebid shows 17+, a very good six card suit, not forcing.
  • Any reverse is 17+, natural, forcing one round.
  • 2N 18-19 HCP, balanced, not forcing.
  • A jump shift is 19+, usually natural, game forcing.
  • If none of the above applies, bid the longest side suit up the line, but always rebid hearts when holding four hearts and five spades.

The last rule can mean bidding a short minor suit. For example, after 1♠ - 1N(forcing),

♠KQJT7 ♥KJT ♦A83 ♣74

has to bid 2♦; and after 1♥ - 1N(forcing),

♠AQJT ♥KJT85 ♦Q4 ♣74

has to bid 2♣!(Could be short). Neither hand may rebid the major, which requires six cards. The second hand does not have enough points for reversing into spades. The 1N bid denied four spades.

Since 2♣ or 2♦ can be two or three cards, responder wishing to sign off should make a preference back to the major with two card support, even with four card support in the minor.

Because you can bid a short suit, rebidding your original suit shows six cards. This is in contrast to your rebid after a two over one bid, in which it does not show six cards.

How Short Is That Minor?

Responder must be very careful to remember that opener may be rebidding a 3-card diamond or club suit, or even a two-card club suit with a 4=5=2=2 shape. But how likely is this?

With 3-3 in the minors opener will bid clubs, so the bid of 2♣ is more likely short than 2♦. With a 5=4=x=x hand, opener will open spades and rebid hearts, but with 4=5=x=x, and not enough points to reverse into spades, opener must bid a short minor. Therefore the minor is more likely to be short after an opening 1♥ than after an opening 1♠.

  • 1♥ – 1N – 2♣ is the most likely to be short;
  • 1♥ – 1N – 2♦ and
  • 1♠ – 1N – 2♣ are less likely to be short; and
  • 1♠ – 1N – 2♦ is least likely to be short.

Responder can be comfortable passing the minor with five in the suit. Responder should prefer back to the major with a doubleton otherwise.

The entire probability of having to bid a short minor is lowered by always opening 1N with a five-card major.

Responder’s Second Bid

Note that responder’s first bid limited his hand to a maximum of 12 points.

If opener has rebid his major, e.g. 1♠ – 1N(forcing) - 2♠, then responder’s bids are:

  • pass with 6-9 HCP
  • raise with 10-12 support points, and 2 or 3 trumps; this is not forcing
  • 2N 10-12 HCP, less than two trump, not forcing. This bid does not promise stops or a NT shape.
  • 3 of a new suit, 10-12, very good 6+ suit, invitational.

If opener has rebid a minor,

  • pass with 6-9 HCP, usually 5+ in the minor, less than 2 of the opener’s major
  • bid 2M with 6-10 HCP, exactly 2 of opener’s major, not forcing.
  • A new suit at the two level is 6-9 HCP, usually 5+ in bid suit, 2 of the major, not forcing.
  • 2N is 10-12 HCP, fewer than 3 of the major, not forcing. Does not promise stops or NT shape.
  • Jump shift is 10-12, very good 6+ card suit, not forcing.
  • Jump raise the major to 3M is 10-12 points, 3 trumps.
  • Raise the minor is 10-12 points, usually 5+ in the suit.
  • Sometimes responder jumps to game with a hand that got better when opener rebid. For example, 1♠ – 1N(forcing) - 2♥ – 4♥.

After a jump shift by opener, e.g. 1♠ – 1N(forcing) - 3♣,

  • responder usually prefers back to opener’s major with 2 card support, or bids 3N with stoppers, even when holding good four card support in the minor. (We are in a game-forcing option, so we can conserve bidding space while showing the 2-card support.)
  • With 3 card support in the major and 10-12 support, responder jumps to game in the major.

The auction 1♠ – 1N! - (2♦ or 2♥) – 3♣ is to play, although with a specially suitable hand opener may make another call.

With a flattish 13-15, but relatively weak holdings in the 4-card suit(s), 1N(forcing) followed by 3N is sometimes appropriate to avoid partner getting too excited.

Two Over One Game Force

If you are not a passed hand, and there is no interference, and your partner opened a suit other than clubs, then…

OK, wait, before I tell you, that was the hard part. When you start playing 2/1 you are going to be getting mixed up because you apply these rules in the wrong context. When you see what looks like a 2/1 bid you have to stop and ask “What has happened so far?”.

Ready? Here we go again.

If you are not a passed hand, and there is no interference, and your partner opened a suit other than clubs, then a two-level response in a new suit is forcing to game or four of a minor. There are six possible sequences:

  • 1♦-2♣
  • 1♥-2♣ or 2♦
  • 1♠-2♣, 2♦, or 2♥

All of these sequences show four card or longer suits with the exception of 1♠ – 2♥, which shows five hearts. Jump bids like 1♦ – 2♠ are not 2/1 bids.

Along with 2/1 we must play 1N Forcing. This means that:

  • As a passed hand, or if there is competition, everything is standard.
  • Over a 1♣ opening, everything (including 1N) is standard.
  • Over a 1♦ opening, 2♣ is game forcing, 3♣ is invitational, and everything else (including 1N) is standard.
  • The game-forcing response of 2♣ or 2♦ can be as little as three cards, such as when responder is 3=4=3=3, in order to be sure 1♠ – 2♥ is five cards.
  • 1♥ – 2♣/♦ does not deny spades.
  • 1M – 2♣/♦/♥ does not deny 3-card support for M. A direct raise, on the other hand, promises four trump.
  • You do not always make a two-over-one bid with game-forcing values. Other choices include Jacoby 2N, inverted minors over 1♦, and bids of 1♥ or 1♠ when available.

Variations in Two Over One

While there is little variation in how 1N forcing is played (some play it as forcing or “semi-forcing” by a passed hand), there are considerable other variations amongst Two Over One players:

  • Since 1♦ did not promise five cards, and a response of 2♣ denies the majors, some do not play this as forcing to game if responder bids 3♣.
  • Some play that jump shifts by responder are weak, others various shades of strong.

When Do You Bypass A Major?

After a 1♥ opener, holding four spades, do you always bid 1♠? No. With game-forcing values and a five-card minor as well as four spades, bid the five-card minor at the 2 level to force to game. To make this work, we agree that a 2♠ rebid by the opener is not a reverse. Thus, if we have a 4-4 spade fit, we will find it. However, do not skip over a five card major suit.

If you do bid 1♠ over 1♥ holding five spades, opener may rebid 1N or 2N. If they do, you can use New Minor Forcing with invitational or better values to find a 5-3 fit.

Many people have trouble recognizing NMF in auctions with a 2N rebid:

1♦ 1♠
2N 3♣!(New Minor Forcing)

When you do decide to respond 1♠ with game-forcing values, it is ok; just be sure that your subsequent bids cannot be passed. NMF and Fourth-Suit Forcing are important tools here.

Opener’s Rebids After 1M - 2x

Once we have made a 2/1 game-forcing bid, if the opponents interfere we either will bid game or double them for penalty. In such a situation if one partner passes the other is forced to double or bid on.

The opener’s rebids after the game-forcing bid are:

  • Simple rebid of 2M is the catch-all bid if nothing else is available. It does not promise extra length or extra strength.
  • Jump rebid to 3M shows extra values and a 6-card solid suit. This sets trumps. Responder’s new suit bids are control bids. E.g., 1♠ – 2♦ – 3♠ – 4♦; 4♦ here is a control bid in diamonds, denying a control in clubs.
  • New suit at the two level is natural, 4 cards, any strength. Note that the new suit can be higher-ranking without showing extra values, i.e. reverses are off. So, for example, 1♥ – 2♣ – 2♠ shows five hearts and four spades, but not extra values.
  • New suit at the 3 level but not a jump: natural, 4+ cards, extra values (15+). This bid will necessarily be in a minor suit. If you don’t have extras, bid 2N if balanced / semi-balanced with stoppers, or rebid your major (catchall).
  • Jump shift to the 3 level is a strong 5-5 with most of the strength in the suits.
  • Jump shift to the 4 level is a splinter in support of responder.
  • 2N shows 12-14 or 18-19 balanced, stoppers in unbid suits. With 18-19 make a slam try if responder signs off to show the bigger hand. Responder assumes 12-14 initially.
  • 3N is 15-17 balanced (only possible if you had decided to open a balanced hand in a five-card major.)
  • 1♠ – 2♥ – 3♥ shows 3 card support, any strength. Not raising hearts denies 3-card heart support. Denies a hand that can splinter or jump raise.
  • Single raise of minor shows extra values, 4 card or good 3-card support. Without extra values bid 2N or catchall rebid of your suit.
  • Jump raise shows most points concentrated in the two suits, denies a first- or second-round control in the other suits.

Here is how I remember that rebidding my suit does not require six cards: We are going to game; we are in no hurry; all I’m doing right now is showing something else about my hand, and if I have nothing else to say, I just repeat myself. I won’t get stuck in a bad fit because partner isn’t going to pass.

Another principle of 2/1 is “slow shows”, also called the principle of fast arrival. The stronger your hand, the slower you go. Arriving at game quickly says you’ve shown your values already. For example:

1♠ – 2♣ – 2♠ – 4♠

Responder has raised opener to game directly. This shows minimal values for game.

1♠ – 2♣ – 2N – 3♠ or 1♠ – 2♣ – 2♠ – 3♠

Responder has raised spades slowly. He has extras and has slam interest. In both cases responder likely has just three spades, as he would have bid Jacoby 2N on his first bid otherwise. Opener should now bid controls.

Fast arrival should apply only in situations where opener is a minimum, having rebid 2N or the catchall rebid of his suit. If opener could be stronger, we don’t want to use up space by jumping; so when we do jump, as in 1♠ – 2♣ – 2♥ – 4♠, it is to paint a picture of our hand has having two suits with our values concentrated in the suits and denying outside controls (A/K/singleton/void).

Responder’s Rebids

  • 2N shows 12-14 or 18-19 balanced, stoppers in unbid suits. With 18-19 make a slam try if opener signs off to show the bigger hand. Opener assumes 12-14 initially.

  • A jump to 3N shows 15-17, stoppers, could be unbalanced if no fit.

  • Rebid responder’s suit shows natural, 5/6+ cards. The game force is still on.

  • New suit is natural, 4+ cards. However if a fit has been established this is a control-bid.

  • If opener has bid 2 of a lower-ranking suit, responder has 3 raises available for opener’s first suit. Fast arrival does not apply because opener is unlimited. For example:

    • 1♠ – 2♣ – 2♥ – 2♠ (no extras)
    • 1♠ – 2♣ – 2♥ – 3♠ (slam interest)
    • 1♠ – 2♣ – 2♥ – 4♠ (picture bid) Two-suited, values concentrated in the suits, no outside controls.
  • A jump in a new suit shows a singleton or void in that suit and support for opener’s last bid major suit. Thus:

    • 1♠ – 2♣ – 2♠ – 4♦!
    • 1♠ – 2♣ – 2N – 4♦!
    • 1♠ – 2♣ – 3♣ – 4♦!

    All show a splinter in diamonds in support of spades.

The auctions that start 1♦ – 2♣

This auction is different because our goal is likely 3N. Opener’s rebids are:

  • 2♦ (catchall) shows 5 diamonds, any strength, does not deny a four-card major.
  • 2N shows 12-14, balanced, stoppers, does not deny a four-card major.
  • 3N shows 18-19 balanced, stoppers
  • 2♥ or 2♠ shows a 4-card major, denies five cards unless suit is rebid on next round to show a 5-6 hand. Does not promise extra strength.