New Minor Forcing: How the Checkback Bid Works

New minor forcing (NMF) is a bid by responder after the auction starts one of a minor, one of a major, 1NT. Responder bids the unbid minor at the two level as an artificial, forcing question: "Do you have three-card support for my major, or four cards in the other major?" It promises at least invitational values and says nothing about the minor you named.

NMF belongs to 2/1 Game Force and Standard American, where the 1NT rebid shows 12-14 balanced. Acol players meet the same problem after a stronger 1NT rebid and usually solve it with Checkback Stayman, covered below.

Picture the auction 1♦ - 1♥ - 1NT. Partner has a balanced minimum, but you still do not know whether partner holds three hearts. With five hearts and game values, that one fact decides between 4♥ and 3NT. You cannot bid 3♥ to ask, because that is a natural invitation, and 2♥ is a sign-off.

NMF solves it. The new minor is the minor nobody has bid:

The bid is forcing for one round. Opener must answer, and responder's next call places the contract or invites. To see how each robot system reads this 2♣, look up 1♦ - 1♥ - 1NT - 2♣.

Use NMF when both of these are true:

1. You have a five-card major, or you responded 1♥ with four hearts and also hold four spades.
2. You have at least invitational values: about 11 HCP or more opposite a 12-14 rebid. Some partnerships play it from 10.

Hands that do not need it:

• Weak with a five-card major: rebid 2 of your major. It is to play.
• Invitational with no major interest: raise to 2NT.
• Game values with only a four-card major: a 4-3 fit is rarely better than 3NT, so bid 3NT.
• Invitational with a six-card major: jump to 3 of your major. That is natural and invitational in standard methods.

Opener answers in a fixed order: support for responder's major first, then the unbid major, then notrump.

The jump to 3♥ with a maximum is common but not universal. Some pairs simply bid 2♥ with any three-card support and let responder decide. Other pairs use the cheapest bid (2♦ here) as the minimum denial and keep 2NT for a hand with good stoppers. Agree which style you play.

Can opener hold four spades after 1♦ - 1♥ - 1NT? Most players rebid 1♠ with four spades, but some prefer 1NT with a flat hand. If your partnership never skips the spades, the 2♠ answer is rare after a heart response.

After the answer, responder knows enough to place the contract:

• Fit found, invitational hand: raise to three of the major if opener showed a minimum. If opener jumped to show a maximum, bid game.
• Fit found, game values: bid four of the major.
• No fit, invitational: pass 2NT, or bid 2NT yourself over a 2♦ answer.
• No fit, game values: bid 3NT.
• Five-five or longer: bid your second suit at the three level, which is natural and forcing.

A useful agreement: when responder bids NMF and then bids two of the major over opener's 2♦, that is invitational with five cards, because the immediate rebid of two of the major was the sign-off.

South has 11 HCP and a five-card heart suit, enough to want game if North has a maximum or a fit. North's 1NT rebid could hold two or three hearts, so South asks with 2♣. North has three hearts and 14 HCP, the top of the range, and jumps to 3♥. South bids 4♥.

Look at the club suit. North's ♣J6 opposite South's ♣954 is no stopper at all. In 3NT, played by North, East leads a club and the defense runs its tricks: the contract goes down on any club lead. In 4♥, North's short clubs are an asset: declarer loses two clubs and a spade, ruffs the third club in dummy, and makes ten tricks with ease. A double dummy solver gives 4♥ eleven tricks and 3NT only eight on a club lead.

Without NMF, South has to guess. That guess costs a game in exactly the hands where the 5-3 fit matters.

These errors come up again and again at the club:

• Passing NMF. It is forcing. Opener with a dead minimum still answers.
• Reading the minor as natural. Responder may have a singleton in the new minor.
• Using NMF with a weak hand. If the answer will not change your plan, the bid only gives the opponents a cheap double to show a lead.
• Skipping the support. Opener with three-card support shows it first, even with four cards in the other major.
• Using it after a suit rebid. NMF applies after the 1NT rebid. After 1♣ - 1♥ - 1♠, a bid of 2♦ is the fourth suit, which is a different tool (see fourth suit forcing).

Two-way NMF splits the work between both minors:

• 2♣ is a puppet: opener must bid 2♦. Responder then passes with a weak hand and long diamonds, or makes an invitational bid.
• 2♦ is an artificial game force. Opener describes the hand, starting with support for responder's major.

The gain is clarity. After the 2♦ game force, every bid below game is forcing, so the partnership has room to look for slam or to choose the right game. After the 2♣ puppet, every bid is at most invitational. Many experienced pairs play this, and the XYZ convention extends the same idea to every one-level rebid by opener.

Checkback Stayman is the Acol cousin. In Acol, with a weak 12-14 1NT opening, opener's 1NT rebid shows 15-17. Responder needs fewer points to look for game, so the question comes earlier: after 1m - 1M - 1NT, responder bids 2♣ as the checkback, no matter which minor opener started with. Opener answers the same way: support first, then the other major, then 2♦ with neither.

Some Standard American players also use 2♣ as checkback in every case. That is fine: what matters is that both of you know whether the minor is natural.

Here is the common version after 1♣ - 1♠ - 1NT - 2♦:

And responder's choices after a 2NT answer:

If a cell in this table differs from what you play, that is normal. Write your version on the convention card.

NMF auctions come up every session, which makes them ideal for practice. In the BridgeDummy Bidding Room you bid random deals with EPBot robots in 2/1 Game Force, SAYC or Acol, so the same 1NT-rebid problems show up hand after hand. The bidding puzzles go one step further: every call you could make is tested over many deals that fit the auction, so you see how often 4M beats 3NT in practice.

Related reading: Stayman uses the same "ask about majors" idea over a 1NT opening, and responder's rebid covers the natural bids around NMF.