People falsely associate Matchpoint scoring with a need to play 3NT at almost every opportunity. In fact it is at Teams that 3NT is more often preferable to 4/4. At Teams, playing in 3NT is bad only if 4/4 makes two more tricks (e.g. 4 makes ten tricks and 3NT makes eight). If you play in 3NT making nine, and then find out that 4 would have made ten, that’s not a tragedy at Teams.
At Pairs, 4/4 will be better if it makes just one more trick than 3NT (eg. 620 in 4 and 600 in 3NT). That extra 20 points really matters. You would want to be in 4/4 if you think there’s one extra trick to be had – and there generally is with a 4-4 fit.
However you must beware of the information that a Stayman enquiry gives. Exercise: Would you bid 2 Stayman over partner’s 1NT opener with these responding hands:
Hand A: A clear Stayman bid. If partner holds four spades it will almost certainly be better to play 4 than 3NT. There is heart weakness for 3NT and even if partner is well-stopped in the suit, there will surely be an extra ruffing trick somewhere.
Hand B: A clear 3NT – with the 4-3-3-3 shape. There will be the odd hand opposite where 4[ plays better than 3NT, but many more where 3NT will make the same number as 4. Even if, facing four spades opposite, there were slightly more hands where 4[ would play a trick better than 3NT (and this I doubt), I would still not bid Stayman. This is because every time partner does not have four spades and you play in 3NT, you have given the defence information about partner’s hand (ie. whether he has four hearts).
Hand C: 2 Stayman. The fact that you have both four-card majors does make a difference. In general, every time you end up in 3NT, you’d rather not have gone via Stayman (giving away information). With two four-card majors as here, you are twice as likely not to play 3NT than if you had just one four-card major.
Hand D: Closest yet. I would bid 3NT, although if partner held four spades I would probably on balance rather be in 4. Reason: I don’t want to give away the information. What if my Stayman bid was doubled, tipping off the club lead? Or, more subtly, what if the Stayman bid wasn’t doubled, so West found (say) the winning heart lead against 3NT rather than the losing club (from equivalent suits). Having said all that, if my heart doubleton was two small, that’s too much risk — I’d bid Stayman and hope for a spade fit. An against-the-field 3NT with a spade fit and the defence cashing all the hearts will score a big, round zero.
When to lean towards Stayman: Small doubletons, or both four-card majors. When to lean towards 3NT: 4333s, or honour doubletons. Look at our featured deal:
The Bidding as it SHOULD have Happened:
North’s decision to look for a 4-4 heart fit was hardly criminal, but once East had found the good lead-directing double of the 2 Stayman, North- South could kiss a decent result goodbye. Against 3NT West led a club to the ten and queen and declarer led a spade, hoping East held A. Not so; West rose with A, whereupon a second club through K-9 ensured four club tricks for East. Down one.
Recommended is a simple jump to 3NT by North, hoping that there isn’t a 4-4 heart fit or that, even if there is, 3NT will play for as many tricks (North’s good outside intermediates making that quite likely). Declarer wins West’s spade lead, knocks out the ace of spades and, later, the ace of clubs. Nine tricks and game made.
[box]4-4 major fits do usually play a trick better than notrumps. But with 4333 shapes and 4432s with good doubletons, it may be best to blast 3NT and give the opponents no information.[/box]