Under what circumstances should partner bid 3 clubs (Stayman) over a 2NT opening?

Question

Opposite a 1NT bid, I need at least 8 high card points to bid Stayman (except for transfer or "garbage" Stayman). If we find our eight card fit and partner has 16, we are barely even money to make four of major with 24 high card points.

How much does one need to bid Stayman opposite a 2NT opener? I'd want about six high card points, or at least five, but my partner did so with four. The following will illustrate my point.

Neither vulnerable, I opened 2NT (20-21 balanced) after two passes. Partner bid 3 clubs (Stayman) with ♠ J842 ♡T954 ♢QJ ♣ 732. I bid three diamonds, denying a four card major.

Partner then raised me to 3NT. We went down big time because one opponent ran clubs (I held Q8 in my 20 point hand). Partner then said, "I think I should have left you in three diamonds."

Was it a good idea for partner to use Stayman to pull me into a suit contract? Should he have passed after I bid three diamonds? Or did the problem originate with my 2NT bid? (I held ♠ AKQ ♡ Q72 ♢AK872 ♣ Q8.)

Answer 1

I have run a simulation from responder's perspective, and the results clearly show that the hand in question is not good enough to bid game in response to a 2NT opener when playing double dummy.

Number of over/undertricks in game
--------------------------------------------------
| Value | Count |      Pct |  Cum Pct |   Pctile |
|-------|-------|----------|----------|----------|
|    -4 |     7 |    0.70% |    0.70% |  100.00% |
|    -3 |    44 |    4.40% |    5.10% |   99.30% |
|    -2 |   233 |   23.30% |   28.40% |   94.90% |
|    -1 |   430 |   43.00% |   71.40% |   71.60% |
|     0 |   255 |   25.50% |   96.90% |   28.60% |
|     1 |    30 |    3.00% |   99.90% |    3.10% |
|     2 |     1 |    0.10% |  100.00% |    0.10% |
|-------|-------|----------|----------|----------|
|       |  1000 |    0.00% |    0.00% |    0.00% |
--------------------------------------------------

The assumptions: opener has 20 or 21 high card points with classic balanced shape (4333, 4432, or 5332 without a 5-card major). When opener has 4 hearts, we play 4 hearts, when they have 4 spades but not 4 hearts, we play 4 spades, and otherwise we play 3NT.

I want to mention briefly that declarer has a slight edge over double dummy results, mostly based on the difficulty of making a good opening lead based only on the auction (see Richard Pavlicek's analysis). However, at the game level that edge is very slight, and I think not enough to tip the scales in favor of bidding game.

It's worth noting that this is about the worst 4=4=2=3 4-count that responder could hold. I played around with a few other honor holdings with that shape, and found that KJ42 T954 32 732 made game a nearly even proposition.

When you change the spade jack into the queen in the original hand, game becomes a clear favorite:

Number of over/undertricks in game
--------------------------------------------------
| Value | Count |      Pct |  Cum Pct |   Pctile |
|-------|-------|----------|----------|----------|
|    -3 |     2 |    2.00% |    2.00% |  100.00% |
|    -2 |     7 |    7.00% |    9.00% |   98.00% |
|    -1 |    33 |   33.00% |   42.00% |   91.00% |
|     0 |    48 |   48.00% |   90.00% |   58.00% |
|     1 |     9 |    9.00% |   99.00% |   10.00% |
|     2 |     1 |    1.00% |  100.00% |    1.00% |
|-------|-------|----------|----------|----------|
|       |   100 |    0.00% |    0.00% |    0.00% |
--------------------------------------------------

I think the conclusion that may be reached here is that most balanced 4-counts should not bid game over a 2NT opening at matchpoints. And, at the risk of over-extrapolating: nearly all 5-counts should bid game over a 2NT opening at all forms of scoring.

The secondary question is: should partner have bid Stayman and then passed? I won't even run a sim to answer that question. The answer is clearly "no". Garbage Stayman is inappropriate without club shortness. Opener only promises two diamonds even when denying any 4-card major, and a 2-2 fit at the three level is an unmitigated disaster. Responder's hand is only mildly positive for a suit contract even if a 4-4 fit is found. There's no need to take such a risk.

Answer 2

I'm going to venture on a limb, and argue that your hand is just shy of a 2NT opening, and worth only 19 points in NT rather than 20. Reasons are:

• Plus 1/2 point for the fifth club. One would often add a full point for this, but that really requires some spot or honour card as the third highest in the suit. The 87 just don't cut it here, particularly when Partner is expected to be weak.
• Minus 1/2 point for the spade AKQ. Part of the value of every high card is a contribution towards setting up small cards in the suit, either as length tricks or creating entries to partner's hand in the suit. Here the spade suit has no small cards, and their absence is a significant flaw in a suit holding half your high card points.
• Minus 1/2 point for the unsupported Qx of clubs. That's a vulnerability to both AK long on your left, and either AJ, AT, KJ, or KT on your left with length in either opposing hand. Even doubleton QT significantly reduces the exposure, hence the full point deduction.
• Minus 1/2 point for the unsupported Qxx in hearts. The vulnerability here is less than in clubs, but still quite real.

That adds up to just 19 true points, with three significant flaws: too few points and too many flaws for a 2 notrump opener.

Alternatively: what is the bare minimum holding from partner that makes 3 NT playable? It would look something like xxx JTx Qxx JTxx; and gives the opponents 2 tricks from AK in both round suits and allows you to set up a ninth trick in either of them. The game now just requires a 3-2 split in diamonds. But that's a perfect minimum, and very unlikely unless partner has one more card value somewhere - that is to say, has a response opposite a 1 diamond opener. Q.E.D.