From: Matthew Vernon <matthew@debian.org>
Date: Mon, 8 Jun 2020 16:03:49 +0000 (+0100)
Subject: Add Multi-Landy overcalls of 1NT, and defences thereto
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~matthewv/git?p=bridge;a=commitdiff_plain;h=f88ef6974d6e6ca8cd5f7daafcd08915cf4d37e7

Add Multi-Landy overcalls of 1NT, and defences thereto
---

diff --git a/convention.txt b/convention.txt
index 202607c..00f86e8 100644
--- a/convention.txt
+++ b/convention.txt
@@ -1,6 +1,7 @@
 * Executive summary:
 
-Acol, 12-14 1NT, Weak twos, transfers, roman key card blackwood
+Acol, 12-14 1NT, Weak twos, transfers, roman key card blackwood, Multi
+Landy overcalls of 1NT
 
 * Magic numbers:
 
@@ -191,6 +192,56 @@ With more points, double, then bid NT next time.
 2[suit] overcall is 6+cards, 12-15ish points
 a game overcall in a major with 6+cards 17+ points can be worth a shot
 
+** Overcalls of 1NT **
+
+Pass - <9 points
+Double - 15+ points (for penalties) [or 19+ facing strong 1NT]
+
+(the following bids are all alertable)
+2C    - 5-4 or 5-5 in the majors
+2D    - a 6-card major with no side suit
+2H/S  - 5 H/S, 4+ in a minor
+2NT   - at least 5-5 in the minors
+3C/3D - 10-15 points, good 6+ card suit
+3H/3S - 7+ cards, 5-9 points, pre-empt
+
+* Response to 2C (which showed 5-4/5-5 majors)
+Pass  - 6+ clubs (non-forcing)
+2D    - equal length in majors
+2H/2S - sign-off preference for H/S
+2NT   - 12-14 balanced (natural, non-forcing)
+3C    - 15+ game-force, artificial
+3D    - 6+ diamonds, 10-14 points
+3H/3S - invitational in H/S
+
+* Response to 2D (showed a 6-card major)
+Pass  - 6+ diamonds(!)
+2H    - sign-off in H OR invitational in S (3S over 2S correction)
+2S    - sign-off in S OR game-going in H (4H over 3H correction)
+2NT   - artificial, game-going [see below]
+
+* Response to 2H/2S (showed a 5-card major, 4+ minor)
+Pass     - 2/3 of the bid suit (and no 4+ minor)
+2NT      - artificial, please bid your minor suit
+3NT      - to play
+3[suit]  - support, invitational to game
+4[suit]  - support, to play
+new suit - denies support, 6+ cards (or 5+ if 2S)
+
+* Response to 2NT (showed at least 5-5 minors)
+3C       - to play
+3D       - to play (denies club support)
+3H/3S    - 6+ in that suit, no minor support
+3NT      - to play
+4C/4D    - 3+ support, invitational
+4H/4S    - to play
+
+* Continuation of 2D-2NT sequence:
+3C    - Hearts, maximal
+3D    - Spades, maximal
+3H    - Hearts, minimum
+3S    - Spades, minimum
+
 ** Doubles **
 
 Takeout double needs about 13 points, shortage in the opponents suit.
@@ -215,3 +266,36 @@ NT doubles are always penalty
 doubles of suit escapes from doubled NT are always penalty
 doubles of openings up to 3[suit] are usually takeouts
 doubles of overcalls up to 2S are usually takeouts
+
+** Defences to overcalls of 1NT **
+
+* Defence to a Natural 2C overcall
+Dble  - Stayman
+otherwise, like response to 1NT
+
+* Defence to other natural overcalls
+Dble for penalties, other bids natural
+
+* Defences to Multi-Landy bids
+(i.e. what to do when partner's 1NT is overcalled thus)
+
+Generally, pass unless you have roughly invitational values (so
+11ish); other bids are natural except:
+
+Against 2C overcall (5-4/5-5 majors):
+Dble   - I can penalize at least one of the majors
+3C     - Natural and forcing
+
+Against 2D overcall (6-card major):
+Dble   - Stayman
+3D     - Natural and forcing
+
+Against 2H/2S (5-card major, 4+ minor):
+dble    - Penalties in the bid suit
+3[suit] - Game-forcing Stayman
+
+Against 2NT (at least 5-5 minors):
+dble    - I can penalize at least one of the minors
+3C      - Stayman, not game forcing
+3D      - Stayman, game forcing
+3H/S    - natural, game forcing