Introduction

If we have established an eight card major suit fit then 3NT is never to play. Conventional uses for 3NT in such auctions include 1/3/3/3NT (Bergen Raises) and 1/2NT/3NT (Jacoby 2NT). In such an auction a 3NT bid which is not otherwise defined is Serious 3NT -- showing extra values and requiring partner to cuebid.

We assume in the following list that the partnership bidding has shown an eight card or longer major suit fit:

  • A 3NT bid not otherwise defined as conventional is Serious 3NT. e.g. 1/2/2NT/3/3NT is Serious 3NT.
  • Serious 3NT does not supersede any convention. i.e. If, absent an agreement to play Serious 3NT, a 3NT bid has a conventional meaning then it retains that meaning.
  • A Serious 3NT bid shows extra values and requires partner to make a cuebid. The cuebid must be in keeping with the principle of Italian Cuebids. i.e. Partner must bid his lowest ranking control of any type -- ace, king, singleton, or void.
  • If hearts are trump then a Serious 3NT which bypasses 3 denies a spade control. e.g. 1/2/2NT/3/3NT. Here the bidder denies a control (ace, king, void, or singleton) in spades. Note that Colin and I play Kickback. Thus if 4 appears in the auction it is Kickback. So this auction's 3NT bypasses the partnership's only chance to cuebid spades.
  • If neither partner has limited his hand then a bidder who bypasses Serious 3NT to cuebid on the four level denies extra values. e.g. 1/2/3/3/4: opener's 4 denies extra values.
  • If one bidder limits his hand then partner may still employ Serious 3NT but here a direct cuebid also shows extra values. e.g. 1/1NT/2/3/... Here responder has at most 12 HCP. So opener needs substantial extra values to look for slam. Thus a cuebid of 4 sends the same message as Serious 3NT: "I have extra values, cuebid if you can." (Opener would choose 3NT if he lacked a club control.)
  • Note that it requires a known eight card fit to make a 3NT bid Serious 3NT. e.g. 1/1/2/3NT. Here 1 promises only four hearts while 2 promises only three. So 3NT is not Serious 3NT, just a natural bid which denies a fifth heart and offers partner a choice of contracts.

Courtesy Cuebids and the Floundering Around Effect

Consider the auction and hands shown below.

West
1
2NT
4
  ?
East
2
3
4
Possible West Hands:
  [1] AJ874 964 A82 A5
  [2] AJT74 QJ4 82 KQ5
  [3] AQJ74 Q6A8 A852
Possible East Hands:   [4] Q65 A7 QJ764 QJ4   [5] K65 AK3 QJ764 74   [6] K65 AK3 QJ7654 7   [7] KQ6 AK3 QJ7654 7

Hands [1], [2], and [3] are all consistent with West's auction. Some might open 1NT with [3] but the hand is too good for that. Others might rebid 3 but we save that bid for longer or stronger clubs than Axxx. Anyone would cuebid 4 with hand [3] since slam prospects look good. And most 2/1 bidders cuebid with hand [1] as well. True, the hand is minimum. But East's hand is as yet unlimited and so West cuebids just in case East has a good hand. Also, since Colin and I use Italian Cuebids, we bid 4 with hand [2] as well. We call the 4 bids with [1] and [2] Courtesy Cuebids.

East's first two bids are a game forcing three card raise showing diamonds and exactly three spades. The auction is automatic for hands [4] - [7]. After West's 4 East, with a heart control and no diamond control, will bid 4 regardless of strength. Even if he is minimum he will be loathe to bid 4 and will make the courtesy cuebid in case West is strong.

Thus either partner may be minimum or strong -- even much stronger than any of the hands shown -- but neither bidder has a clue as to his partner's extra strength, if any. In short, they are floundering around and cannot know how to proceed.

Suppose that West has hand [1]. If he bids anything but 4 over 4 he will get too high opposite [4] or [5]. So he must subside. And certainly he must bid 4 holding hand [2]. Now suppose that West does bid 4 and catches East with hand [7]. What should East do? If he bids on he may find West with [2] -- down one in 5. But if he passes he may find West with hand [1] and miss a slam.

Serious 3NT is often helpful in situations of this type. We consider a few examples.

West
AJ874
954
A82
A5

    1
    2NT
    4
    Pass
East
K65
AK3
QJ764
74

    2
    3
    4
This is hand [1] vs. hand [5]. West's 4, bypassing 3NT, shows a minimum hand. Then East, without hope of slam, bids the game. Note that a cuebid of 4 here would show extra values, saying "I don't care if you are minimum, we may still have a slam." East would bid the same with [4] or [6]. And of course West would bid the same with [2].

The inferences drawn from a failure to bid Serious 3NT are an important part of this convention and should always be kept in mind.
West
AJ874
954
A82
A5

    1
    2NT
    4
    4NT
    5NT
    Pass
East
KQ6
AK3
QJ7654
7

    2
    3
    4
    5
    6
This is hand [1] vs hand [7]. West appears to have gone crazy after East's 4. But West, for his previous bidding, has a monster. If three aces and the jack of spades won't produce a slam then East should not have cuebid. (Compare with the previous note.) Furthermore, West, with his three aces, must take charge -- to cuebid 5 would serve no purpose other than torturing partner. After East's 5 West knows the partnership has all the key cards and, since East has not yet limited his hand, West lets East know that by bidding 5NT. Although this bid nominally asks for kings East understands that the grand slam decision is his and just signs off in 6.
West
AJT74
QJ4
82
KQ5


    1
    2NT
    4
    4
East
KQ6
AK3
QJ7654
7

    2
    3
    4
    Pass
This is hand [2] vs hand [7]. West, knowing the partnership is off two top diamonds, attempts to sign off. This does not actually deny a diamond control. But East who would need West to have a near perfect hand (see previous example) is content to stop.
AQJ74
Q6
A8
A852

    1
    2NT
    3NT
    4
    4NT
    6
K65
AK3
QJ7654
7

    2
    3
    4
    4
    5
    Pass
This is hand [3] vs hand [6]. Here West's Serious 3NT has the incidental consequence of eliciting 4 from East -- just what West wanted to hear. The 4 bid is the other thing he wanted to hear and the slam is reached.

Comments

Serious 3NT is simple and straightforward. It makes use of a bid which is not otherwise used. It is often of great value and very rarely creates any difficulty. For these reasons it has been widely adopted by experts who play two over one.

Some pairs play Non-Serious 3NT. In this convention 3NT denies extra values while a cuebid which bypasses 3NT shows extra values. I believe that our convention is more common but cannot see that one treatment is theoretically better than the other.