CROWHURST CONVENTION
What Is It?
The Crowhurst Convention is a mechanism whereby following a 1NT re-bid from opener, the responder can ask opener to define his no-trump range more accurately and also show additional features.
It was originally developed by Eric Crowhurst to cater for the wide ranging 12 – 16 1NT rebid, but can equally be used in response to the more modern 15 – 17 point no-trump rebid (or 15 – 18 with a slight adjustment to the relevant points).
Mechanism
Details differ, but the basis is that following opener’s 1NT rebid (15-17 points), a 2♣ bid by responder asks opener to define his hand in terms of minimum (15, poor 16 points), or maximum (good 16, 17 points).
Responder’s points will normally be in the 7 – 9 range (but can also be used on higher point hands to assess the best game contract, and also to consider slam possibilities opposite a maximum response from partner)
Opposite any maximum response it is game forcing.
The corollary is that if responder does not use the 2♣ bid, any alternative bid tends to show weakness (some partnerships may treat this differently).
Opener’s Responses to 2♣
Lower range (15, poor 16 points)
Support responder’s suit with 3 card support
(e.g. 1♦ - 1♠ - 1NT - 2♣ - 2♠…)
Bid any new suit below 2NT
(e.g. 1♦ - 1♥ - 1NT - 2♣ - 2♠…) (this is not a reverse from opener)
Re-bid own suit with 5-card suit (with 5 card majors, good 5 or 6 card suit)
(e.g. 1♥ - 1♠ - 1NT - 2♣ - 2♥…)
If neither (a) nor (b), bid 2♦
(e.g. 1♣ - 1♥ - 1NT - 2♣ - 2♥…)
Upper range (good 16, 17 points)
Support responder’s suit by bidding it at the 3-level.
(e.g. 1♦ - 1♠ - 1NT - 2♣ - 3♠)
With extra length in own suit, re-bid suit at 3-level
(e.g. 1♥ - 1♠ - 1NT - 2♣ - 3♥… shows a 5 card suit or 6 card if playing 5-card majors)
With second suit, bid suit at 3-level
(e.g. 1♣ - 1♥ - 1NT - 2♣ - 3♠… shows a 4-card spade suit
It’s important that if there is a choice of the three above options, the appropriate ones must be bid in sequence, with a view to showing any other option in the subsequent bidding.
(e.g. 1♦ - 1♠ - 1NT - 2♣ - 3♦ - 3♥ - 3♠ - 3NT – 4♥)…. Opener now has 16 or 17 points, and in sequence has shown 5 diamonds, 3 spades, 4 hearts.
(This approach avoids confusion in sequences such as 1♦ - 1♠ - 1NT - 2♣ - 3♣ - 4♦. The 4♦ bidder cannot now be cue-bidding agreeing spades, nor can he be asking opener if he has a five card diamond suit – yes he has, together with four clubs. Responder is just showing diamond support, inviting a cue-bid for a possible slam. Moreover if responder had bid 4NT instead of 4♦, this would be key-card in clubs)
With none of the above, bid 2NT
Other issues
Following opener’s 1NT re-bid, a bid of 2NT by responder shows a suitable 8 count, requesting opener to bid 3NT with any 16+ hand (seldom used - this particular bid has much more significance when playing a 12 – 16 1NT rebid)
If responder does not use the 2♣ bid, any other natural rebid at the two level (also a jump to 3♣) is weak.This tends to imply a 6-4 distribution, i.e. prepared to play at the three level in the 6-card suit. With most other distributions, he would be inclined to pass 1NT.
Examples: (where the sequences differ between 4 and 5 card majors, these are indicated).
((a) – (e) North has a ‘weak’ 1NT rebid)
a)♠ A72b)♠ A7c)♠ A7d)♠ AJ63e)♠ A763
♥ KJ532♥ KQ532♥ J7642♥ 8♥ J3
♦ A86♦ A86♦ AK5♦ K54♦ AK9
♣ K4♣ Q43♣ K104♣ AK1084♣ KJ73
♠ K9843♠ K9843♠ Q9843♠ Q854♠ J8
♥ 64♥ 64♥ Q95♥ KJ9642♥ Q764
♦ K97♦ K97♦ 964♦ 9♦ 5
♣ J63♣ K62♣ QJ8♣ 63♣ Q98754
a) 1♥ - 1♠ - 1NT - 2♣ - 2♠ - pass. North shows a minimum and three card support for partner. If South had only four spades he would bid 2NT which North would pass.
b) 1♥ - 1♠ - 1NT - 2♣ - 2♥ - 2NT - pass. North shows a minimum and good hearts (even playing an original 5-card major suit, the heart suit is worth repeating due to the good quality). If South had three card heart support, he would pass 2♥, or possibly bid 3♥ further inviting North.
c) 1♥ - 1♠ - 1NT - 2♣ - 2♦ - 2♥ – pass. North shows a minimum and poor hearts (even with a five card suit). South gives delayed support for hearts, which North is now happy to pass.
d) 1♣ - 1♥ - 1NT - 2♠ - pass. The fact that South does not bid 2♣ indicates that 2♠ is a weakness bid (this is not a responder reverse). With good spade support, North passes (probably also if he had a good three card suit). Without support, and a three card heart suit, North would probably bid 3♥.
e) 1♣ - 1♥ - 1NT - 3♣ - pass. South cannot bid 2♣ (which would be Crowhurst), and is not happy with 1NT, so has to bid 3♣ directly. Having not gone through the 2♣ Crowhurst, North realises that this is a weakness bid (this is not a three level force). North must pass.
((f) – (i) North has a ‘strong’ 1NT rebid)
f)♠ A72g)♠ A3h)♠ K75i)♠ 86
♥ AQ532♥ AQ9532♥ AK5♥ AQ532
♦ A86♦ AK8♦ K643♦ AK75
♣ K4♣ 843♣ K104♣ A94
♠ K9843♠ K984♠ AQ984♠ K9754
♥ 64♥ KJ♥ Q764♥ K6
♦ K97♦ J107♦ A7♦ Q9643
♣ J63♣ 9752♣ A5♣ 6
f) 4-card majors: 1♥ - 1♠ - 1NT - 2♣ - 3♥ - 3♠ - 4♠. North shows a maximum and good hearts. South shows his 5-card spade suit, and North bids the spade game. Over 3♥, if South had three card heart support, he would eventually bid 4♥.
5-card majors: 1♥ - 1♠ - 1NT - 2♣ - 3♠ - 4♠. North shows a maximum and three card spade support (he’s already shown his five hearts), which South raises to game.
g) 1♥ - 1♠ - 1NT - 2♣ - 3♥ - 4♥. Only 2-card support, but opener shows a six-card suit (playing 5-card majors), or a good 5-card suit(4-card majors).
With an 8-count, an option is to bid 2NT, but with even the remotest fit for opener’s bid, 2♣ enables a better clarification of the hand.
h) 1♦ - 1♠ -1NT - 2♣ - 3♠ - 4NT…6♠. With opener’s maximum response and spade support, South is fairly confident about the slam (as opposed to if opener shows a minimum point count).
i) 1♥ - 1♠ - 1NT - 2♣ - 3♦ - 3♠ - 3NT - 5♦. With opener’s jump to 3♦ showing a maximum and a diamond suit, it’s still important that South re-bids his spades (showing five). North hasn’t denied three card spade suit (he would bid 3♥ before 3♠).
AFH