P16

From Simplex

PRINCIPLE 16: In response to an opening of One or Two of a Suit, responder shows a hand worth a good raise to at least Three of the Suit — i.e. 10+ HCP and 9+ trumps between them — by bidding the Simplex 2NT. If Responder bids a suit on the 1st round, a rebid by opener of 2NT shows that opener has 10+ HCP and that the pair have at least nine cards in responder's suit. And if Opener changes suit on the second round, Responder can bid the Simplex 2NT in reply, showing 10-16 HCP and 4+ card support for Opener's second suit — e.g. 1♥:1♠, 2♣:2NT.