My last two articles focused on opener's rebid problems in 2/1 auctions. When opener's 2M rebid is nebulous, later bidding sometimes gets difficult, because responder may not know which hand type opener holds.

A similar problem can occur when responder can not adequately differentiate his possible shapes. Playing the common combination of 2/1 game forcing, a semi-forcing NT, and Jacoby 2NT, what do you respond with this hand:

1NT is out because we must make a forcing call. 

2NT is out because our support isn't strong enough for Jacoby 2NT.

Where does that leave us? It leaves us with a 2♦ response on our scrawny ♦Jxxx suit. If that feels wrong to you, I agree—2♦ makes me ill. But what are the alternatives?

Before we look into possible alternatives, let's delve into why a 2/1 in a bad suit can cause bidding problems later in the auction.

Frequently responding in four-card suits means opener must be cautious when raising responder. Opener will need four-card support if a raise to 3m is to always suggest an adequate fit for a trump contract. If opener raises on 3-card support, the partnership may have only a 7-card fit and then responder may not be sure when to look for a slam. Conversely, the requirement to hold 4-card support for a raise means opener is forced into awkward choices any time he holds only 3-card support. For example:

Does responder hold four poor diamonds and a notrumpy hand like:

Or has responder bid 3NT holding a more suit-oriented and slammish hand, but taking his last opportunity to show stoppers in both unbid suits, as shown below:

The Balanced Hand Principle

The balanced-hand principle states that when one hand is balanced and the other distributional, the distributional hand should show its shape, and the balanced hand should evaluate the degree of fit (and place the final contract). Once the shortness is known, the balanced hand is better positioned to understand whether the partnership does or does not have wastage (and hence whether a slam contract is or is not realistic).

The balanced-hand principle is the driver for all modern bidding methods over a 1NT opening. In pretty much all modern methods, responder shows his pattern when slam is possible, allowing opener to evaluate when a fit is present, and when his high cards will be working well.

The balanced-hand principle applies just as firmly to auctions after opener has opened 1M. The difference is that opener often has the shapely hand, and responder may be balanced. 

The Swiss raise, and to lesser extent the natural 2NT response, raise the auction to a high level before opener has described his shape. This can sometimes lead to guessing games in slam auctions. 

Suppose an auction begins:

South has a nice hand, and slam is possible if responder has little wastage opposite opener's diamond void. Unfortunately, opener's second suit is hearts. If opener tries for slam by cueing 4♥, how is partner supposed to know that ♣AK is golden and ♦AK is worthless? If opener cues 4♦ instead, how is responder supposed to know that ♦KQxx, which is wonderful opposite ♦A, is waste paper? There simply is not enough room left below game to reasonably sort out all the hand types opener might hold.

Look at how much easier the judgment problem gets when the early auction permits more bidding room:

Opener is able to show his three-suited pattern at the 3-level. Responder is now excellently placed to judge whether his cards fit well, and hence, whether cooperation in a slam search is justified. Further, we have the 3-level as well as the 4-level to do our exploring.

The same problem--consuming bidding room prematurely--can bite even in the lower 1M - 2NT (natural) sequence. 

What should responder bid now? If opener's shortness is in clubs, 3NT could be in jeopardy or a slam could be cold. On the other hand, 3NT will often be a routine contract, and responder has no bidding room to discover the remainder of opener's pattern. So he's left to guess. Once again, the auction would flow more smoothly if responder could bid out his pattern cheaply. For example:

Now responder has been warned that 3NT is in jeopardy when slam in a 4-3 diamond fit might make!

What Lesson Can We Learn?

We can derive some general bidding guidelines from the balanced hand principle:

• Strong balanced hands should bid slowly to leave room for a potentially unbalanced partner to describe his pattern.
   
• Space-consuming jump bids should be used primarily to show shapely hands, often with a fit, or to place the contract when partner is tightly limited.

So with this in mind, is there a better way to handle game-forcing balanced hands after a 1M opening?

The Nebulous 2♣ 2/1 response

Modern experts have adopted a new approach to handling strong balanced hands facing a 1M opening: the two-way 2♣ response. Using this method, 

1♠ - 2♥ and 1M - 2♦ guarantee a 5+ card suit and game-forcing values. Subsequent bidding is natural, and can follow either the Lawrence or Bergen styles, depending on your preference.

1M - 2♣ becomes a nebulous game-forcing call. Responder will have either:

• Any balanced game-forcing hand with 2+ clubs
• A traditional game-forcing hand with a 5+card club suit

Responder will clarify later which of the two hand types he holds. After an initial 1M - 2♣ start, my response structure is outlined below:

1♠ - 2♣

2♦ = a waiting bid showing either diamonds, or any 5-3-3-2 (with any doubleton) hand with insufficient stoppers for 2NT. Since the initial 2♣ response was artificial, opener cannot assume clubs are stopped, so 2NT is a fairly uncommon rebid.

2♥ = 4+ hearts. Unchanged from standard.

2♠ = 6+ spades

2NT = balanced min with some semblance of stoppers in all suits 

3♣ = 4+ clubs

3♦/♥ = splinter raises of clubs

1♥ - 2♣

2♠ = 4-spades and no extras promised, Bergen style. (otherwise opener rebids as above).

As you can see, opener rebids naturally for the most part.

• The 2M rebid promises a 6+ card major, providing the benefits of the Bergen-style 2M rebid.
  
  
• The 2NT rebid promises a NT-oriented, stopper-rich hand similar to a Lawrence 2NT rebid.
  
  
• "Raising" clubs as opener promises 4 clubs. Think of it as rebidding a club suit of your own, not raising since responder frequently holds only 2-3 clubs. Since opener did not splinter, the 3♣ promises exactly 5-2-2-4 distribution.
  
  
• With a splinter raise, opener is artificially describing his pattern as 5-1-3-4, 5-3-1-4 or 5-1-2-5, 5-2-1-5. Responder will be enthused if he holds a 5+ card club suit and if he does not, his knowledge of opener's precise shape will help him judge whether 3NT is a good contract.
  
  
• When opener is 5-4-1-3 or 5-1-4-3, he always rebids a second suit planning to bid 3♣ later to complete the description of his pattern.

Even though opener has no idea what responder holds when he responds 2♣, this method works well when responder is balanced. Opener now has space to begin describing his shape before responder bids 2NT. For example:

1♥ - 2♣ - 2♦

Since 2♦ leaves the most bidding room, it is most easily adopted as the "holder" for hands not easily described with a natural bid. 2♦ is bid with most of the 5-3-3-2 family of hands or with a major and diamonds; opener will clarify later. For example:

Opener showed a minimum hand in the 5-3-3-2 family.

Opener had exactly five spades, one heart, four diamonds and three clubs.

Opener was 5-5 in spades and diamonds.

Responder's Continuations after 2♦

Responder's primary goal after opener's nebulous 2♦ rebid is to communicate whether he holds the balanced or the natural 2♣ hand type. His continuations are natural with one exception.

1M - 2♣ - 2♦ - ?

2M = 3+ card support for opener's major (either balanced or unbalanced)

2oM = (two of the other major) Artificial. Shows an unbalanced hand with 5+ clubs.

When responder's hand is balanced, he will either:

• Show 3-card support for opener's major
• Rebid in NT

When responder's hand is unbalanced with 5+ clubs, he can either:

• Raise at his second turn with a fit
• Bid something other than 2M or 2NT

When responder does not fit opener's major, he frequently bids the other major (artificial). For example:

This call says only that responder is unbalanced and does not fit opener's major. He could have any side suit shape. The purpose is to allow opener to show 3-card support for responder's club suit, at the 3-level, if he has it. Without this convention, responder would frequently have to rebid 3♣ to show his real club suit and opener would then be forced to raise to 4♣ if he wanted to show a fit. By using 2 of the other major instead, opener can show his fit and still leave the 3-level for club/NT exploration. 

After this auction, the partnership has taken a tortuous route to replicate a simple, standard 2/1 auction: 1M - 2♣ - 3♣. Subsequent bidding is similar to that familiar auction.

Review of Artificial Calls

Here is a review of the artificial calls. Other than these bids, bidding is natural and similar to standard 2/1 methods.

1M - 2♣ = either balanced or clubs

1M - 2♣ - 2♦ = either balanced or diamonds

1M - 2♣ - 2♦ - 2oM = unbalanced with 5+ clubs and no support for opener's major

Conclusion

The nebulous 2♣ convention allows the other 2/1 calls (2♦, 2♥) to promise 5+ cards in the suit clarifying responder's hand type. When responder holds a balanced GF hand, it leaves maximum room for opener to pattern out. Compared to responding in the better 4-card minor, the nebulous 2♣ improves bidding accuracy when responder holds either hand type. When responder holds an unbalanced GF hand with long clubs, the auction is occasionally more difficult than with the "standard" 2/1 approach. But the benefits of staying low on balanced hands and better descriptive 2♦ and 2♥ auctions far outweighs the drawbacks.

Postscript

I wish I could credit the originator of the nebulous 2♣ treatment. I learned it from Eddie Wold's system notes and invented my own responses and follow ups. If you know who originated or developed these ideas please chime in with a comment; if you have a better set of rebids and follow-ups, please share. Thanks!