Other continuations

Bidding sequence	Opener's possible continuations other than Pass
1C/1D > 1NT	2C/2D	12-16 unbalanced
	2NT	18 balanced
	3C/3D	17-21 unbalanced
	3NT	19 balanced
	4C	Gerber
1D > 2C	2D/3C	Denies stopper in either major
	2H/2S	Stopper-asking
	2NT	Both majors well-stopped
1C > 2D	2H/2S	Stopper-asking
	2NT	12-14 balanced, both majors well-stopped
	3C/3D	Denies stopper in either major
	3NT	16-19 balanced, both majors well-stopped
	4C	Gerber
1C/1D > 2NT	3NT	To play
1C > 3C	3D/3H/3S (!!)	HSGT
	3NT/5C	To play
	4C	Invite to 5C
	4D/4H/4S (!!)	HSST
	4NT	Blackwood
1D > 3D	3H/3S (!!)	HSGT
	3NT/5D	To play
	4D	Invite to 5D
	4C/4H/4S (!!)	HSST
	4NT	Blackwood
1C/1D > 3NT	4C	Gerber

Note that if opener rebids the opening minor, it promises 6+ cards in case of a 1H response, but only 5+ cards in case of a 1D/1S/1NT response. This is summarised as follows:

Bidding sequence	Number of cards in opening minor	Extreme case (C-D-H-S)
1C > 1D > 2C	5+	5-0-4-4
1C > 1H > 2C	6+	6-1-3-3
1C > 1S > 2C	5+	5-1-4-3
1C > 1NT > 2C	5+	5-0-4-4
1D > 1H > 2D	6+	1-6-3-3
1D > 1S > 2D	5+	1-5-4-3
1D > 1NT > 2D	5+	5-0-4-4

Remarks:

• With a 4-4-4-1 hand (1 in the unbid minor), opener should stay with NT after 1m > 1NT.
• In some cases the number of cards would become 6+ upon opponent's interference. For instance, while 1D > 1S > 2D promises 5+ diamonds (with extreme case 1-5-4-3), 1D > 1S > (2C) > 2D would promise 6+ diamonds (with extreme case 1-6-4-2) since opener could use support double to show 3 spades.
• After confirming no major fit (e.g. 1C > 1D, 1C > 1NT or 1D > 2D), bidding a major (with or without minor fit, and with or without interference) is stopper-asking.