Developments after 1NT > 2C

After 1NT > 2C > 2D,

Bid	Meaning	Continuations
2H/2S	Invite to game with 5-4 in majors (5 in suit bid)	Pass or bid 2NT to reject the invitation Bid 3NT / 4M to accept the invitation
2NT	Invite to game without major fit	Pass to reject the invitation Bid 3NT to accept the invitation
3C (!!)	Shortness in hearts (GF with 4 spades)	Bid 3NT with stopper in hearts Bid a new suit otherwise
3D (!!)	Shortness in spades (GF with 4 hearts)	Bid 3NT with stopper in spades Bid a new suit otherwise
3H/3S	GF with 5-4 in majors (5 in suit bid)	Choose between 3NT and 4M
3NT	To play (10-14, with 4 cards in a major or both)
4C	Gerber (15+ with 4 cards in a major or both)

After 1NT > 2C > 2H,

Bid	Meaning	Continuations
2S	Invite to game with 4 spades (and without 4 hearts)	Pass or bid 2NT to reject the invitation -- After 2NT, a subsequent 3m shows shortness Bid 3NT / 4S to accept the invitation
2NT	Invite to game without 4-card major	Pass to reject the invitation Bid 3H to show 5 hearts (accept INV) Bid 3S to show 4 hearts and 5 spades (accept INV) Bid 3NT to accept the invitation
3H	Invite to game with 4+ hearts	Pass to reject the invitation Bid 4H to accept the invitation
3S	GF with 4 spades (and without 4 hearts)	Choose between 3NT and 4S
4C/4D	HSST
4H	To play (10-14, with 4+ hearts)
4S	HSST
4NT	Blackwood (15+ with 4+ hearts)

After 1NT > 2C > 2S,

Bid	Meaning	Continuations
2NT	Invite to game (without 4 spades, hearts unknown)	Pass to reject the invitation Bid 3S to show 5 spades (accept INV) Bid 3NT to accept the invitation
3C/3D (!!)	Shortness in the suit bid, GF with 4 spades	Bid 3NT with stopper in the suit bid Bid a new suit otherwise
3S	Invite to game with 4+ spades	Pass to reject the invitation Bid 4S to accept the invitation
4C/4D/4H	HSST
4S	To play (10-14, with 4+ spades)
4NT	Blackwood (15+ with 4+ spades)

Notes on shortness:

• After 1NT > 2C > 2D, shortness in minors will not be shown.
• Although showing shortness implies GF value, the bidding may occasionally stop at 4m in case of no stopper in responder's short suit and the absence of a fit.