After a 1st-round Double

From Simplex

The Principles of 1st-round Doubling

Simplex Principles of 1st-round Doubling

PRINCIPLE 11: If a bidder cannot make the first-round bid his hand merits (because the opposition have already taken the auction too high), the bidder simply doubles, with an implied message to partner: "RHO has just taken my opening bid away, and I believe it is safe for you to bid at this or one level higher." PRINCIPLE 13: Ignore first-round doubles by the opponents. Carry on and make the bid you would have made if the opponents had passed. PRINCIPLE 17: Be very wary about doubling when both opener and responder have taken your bid away. You are usually too weak. (For example, you have a hand worth opening 1♣ but the bidding has already gone (1♦):Pass:(1♠).) Exceptionally you can double at the one and two levels when you have 11+ HCP and you are distributional (e.g. a 5-5 shape or a 6+ card suit). PRINCIPLE 30: Do not double their strong (i.e. 16+ HCP), natural bids.

The Principles for Responder's 1st Round Bid

Simplex Principles of Responses to a 1st-round Double

PRINCIPLE 0: Almost always open, overcall and respond with your clearly longest suit. (That is, except when responding to an opening/overcall of Three of a Suit, when it is often better to bid one's cheapest 4+ card suit.) PRINCIPLE 22: Always bid the cheaper of two equal-length suits.

1st Round Bids available to Responder

Box R1A (Version 1.0)	Responding to One of a Suit (1♣, 1♦, 1♥, 1♠)
Bid	Meaning	Forcing?	Where to next?
Pass	0-7 HCP and less than 3-card support for partner's suit	NF
Double	Unable even to bid 1NT. RHO's overcall has taken his bid away.	NF	Box O2A
One of a New Suit	5+ cards, 8-16 points, compliant with Rule of 18.	NF	Box O2B
1NT	8-16 HCP and no other available bid — i.e. the 'dustbin' bid. The hand will contain fewer than four cards in opener's suit. The hand may contain four cards in another suit, or a 5-card suit not now biddable at the 1-level.	NF	Box O2B
Two of a New Suit	6+ cards and 3-16 points	NF	Box O2B
Raise to Two of the Suit	3-card support and 0-9 HCP	NF	Box O2C
2NT	4+ card support and 10+ HCP	F	Box O2B
Three of a New Suit	4+ cards and 17+ HCP	GF	Box O2B
Raise to Three of the Suit	4-card support and 0-9 HCP	NF	Box O2D
Raise to Four of the Suit	5-card support and 0-9 HCP	NF	Box O2E
Raise to Five of Opener's Minor	6+card support and 0-9 HCP	NF	Box O2F

The Principles for Opener's/Overcaller's 2nd Round Bid

Simplex Principles of 1st Round Responses to One of a Suit

PRINCIPLE 6: If Opener/Overcaller rebids his suit on the second round, this shows a suit longer than the five cards originally promised. A simple rebid — e.g. 1♥ then 2♥ — shows a 6-card suit. A jump rebid — e.g. 1♣ then 3♣ — shows a 7-card suit. (NB This principle is not enforced if responder showed a strong hand in the first round — i.e. 2NT, 3x, or 4NT.) PRINCIPLE 7: No extra values are needed to bid any 4+ card suit at the two-level on the second round. There is no concept of a 'barrier' or a 'reverse'. PRINCIPLE 9: Simplex is a fundamentally natural bidding system. The only gadgets used are 2♣ Redshift, 4NT Blackwood, and the Simplex 2NT. PRINCIPLE 12: After a suit-raise by partner — e.g. 1♦:2♦ or 1♥:3♥ or 1♠:4♠ or 1♣:5♣ — do not bid on. That is, unless the opponents are trying to steal your contract and you have extra suit length beyond the five cards your initial bid promised. PRINCIPLE 20: After opening/overcalling One of a Suit or 1NT or doubling on the first round, you can bid another 4+ card suit at the 2-level on the second round, even if responder passed. PRINCIPLE 21: If you had a hand worth opening at the 1-level and you have another 5+ card suit, you should bid it at the 3-level on the second round, even if responder passed. PRINCIPLE 26: After the second round, your doubles are for penalties — do not double purely because RHO has just taken your bid away. PRINCIPLE 28: 2NT in reply to a suit bid is always the Simplex convention. 2NT in reply to 1NT is always quantitative, showing 12-14 HCP balanced.

Box O2B (Version 1.0)	Opener's Rebid after opening One of a Suit (1♣, 1♦, 1♥, 1♠)
Responder's Bid	Opener's Rebids	Meaning	Forcing?	Where to next?
One of a New Suit	Pass	Minimum opening hand (i.e. 8-12 HCP), little support for responder, no other 4+ card suit.	NF
	One or Two of a New Suit	4+ card suit.	NF
	1NT	11-16 HCP and fairly balanced with a 5-card suit.	NF
	Rebid of Opener's original suit at the 2-level	6-card suit.	NF
	Raise Responder's suit to the 2-level	3-card support and less than 10 HCP.	NF
	2NT	The Simplex 2NT: 10+ HCP and 4+ card support for Responder's suit.	NF
	Rebid of Opener's original suit at the 3-level	7+ card suit.	NF
	Raise Responder's suit to the 3-level	4-card support and less than 10 HCP.	NF
	Raise Responder's suit to the 4-level	5-card support and less than 10 HCP.	NF
	Raise Responder's minor to the 5-level	6-card support and less than 10 HCP.	NF
1NT	Pass	8-10 HCP and a 5-3-3-2 shape.	NF
	Rebid of Opener's original suit at the 2-level	6-card suit.	NF
	Two of a New Suit	4+ card suit.	NF
	2NT	12-14 HCP, balanced or semi-balanced.	NF
	Rebid of Opener's original suit at the 3-level	7+ card suit.	NF
	3NT	15+ HCP, balanced.	NF
Two of a New Suit	Pass	Minimum opening hand (i.e. 8-12 HCP), little support for responder, no other 4+ card suit.	NF
	Two of a New Suit	4+ card suit.	NF
	Rebid of Opener's original suit at the 2-level	6-card suit.	NF
	2NT	The Simplex 2NT: 10+ HCP and 4+ card support for Responder's suit.	NF
	Raise Responder's suit to the 3-level	3-card support and less than 10 HCP.	NF
	New Suit at the 3-level	5+ card suit.	NF
	Rebid of Opener's original suit at the 3-level	7+ card suit.	NF
	Raise Responder's suit to the 4-level	4-card support and less than 10 HCP.	NF
	Raise Responder's minor to the 5-level	5-card support and less than 10 HCP.	NF
2NT	Rebid of Opener's suit at the 3-level	Up to 13 HCP.	NF
	Cue-bid of cheapest 1st-round control	14+ HCP.	F
Three of a New Suit	Rebid of Opener's original suit at the 3-level	Minimum opening hand (i.e. 8-12 HCP), less than 4-card support for responder, no other 4+ card suit biddable at the 3-level.	NF
	Three of a New Suit	4+ card suit.	NF
	3NT	Balanced, preferably with the other two suits stopped.	NF
	Rebid of Opener's original suit at the 4-level	6+ card suit.	NF
	Raise Responder's suit to the 4-level	3+ card support and 8-12 HCP.	NF
	4NT	Blackwood: 13+ HCP.	NF

2nd Round Bids available to Opener/Overcaller