CROWHURST

Used only in the sequences:



1X - 1Y - 1NT - 2...
or 1X-(1Y opp)-*(Partner)-1NT-2
or 1X-(* opp)-**(partner)-1NT-2

2 is Forcing. Showing a minimum of 9+ HCP
Opener's 1NT rebid shows 12-16 HCP

Opener's continuations are:

3Y              Shows 3 card Y and 15-16 HCP
3Ma            Shows an unbid 4 card major - in a 4432 distribution where 'Y' is 2 card
3               Shows 16 HCP
3               If not 'X' or 'Y' shows 4 Diamonds  e.g. 1-1 - 1NT - 2 - 3 & 15-16 HCP.                                     Also 1-1H - 1NT - 2 - 3 Shows 5 diamonds & 15-16 HCP
2Y               Shows 3 card support for 'Y' and 12-14 HCP
2Ma            Shows an unbid 4 card Major suit  - in a 4432 distribution
2X               Shows 5 card suit & 12-14 HCP
'Ma' in the above sequences is not 'X' or 'Y'  ('Y' may be the other Major - Ma') & 'X' is not Diamonds.
2NT              Shows 15 HCP or a very good 14 but only as long as 2X & 2Y above are not valid
2                None of the above, 12-14 HCP

Now responder has a clear view of partner's strength and distribution, the final contract can be selected. If responder is strong enough (2 is unlimited) he can use ERKCB.