MOSCITO BYTE 1.0: 1N AND 2m OPENINGS ------------------------------------ by David Morgan, Canberra, Australia (dmorgan@webone.com.au) The 1N structure is based on the Scanian model (developed primarily by Lindqvist, Nilsland and Wirgren). It was modified because the 1N opening in MB 1.0 is much more limited in shape: no five-card major and a four-card major only if opener is 4333. It was also modified to (1) improve bidding of slam- and game-going hands by incorporating relays and stopper-asking bids (including after searching for a major-suit fit), (2) allow responder to choose to be declarer with 5+M (as opener has a minimum normal opening, responder will often have as many, if not more, tenaces to protect), and (3) enable responder to show the strength of a long suit when making a slam try. It sacrifices some INV sequences (e.g. if responder chooses to show INV values with a six-card minor or a four-card major and a longer minor, then the sequence must end in 2N -- he does not have the option of one ending in 3m). It provides a wide range of options when responder has no game interest, including often being able to play in 2D. Importantly, this structure is designed to (1) minimise the amount of information provided to the opponents about the likely declarer's hand, and (2) make best use of the balanced hand principle (Morgan, The Bridge World, December 1989): that unbalanced hands should describe themselves to the balanced hand, which is better placed to determine how well the hands fit. There is one change from the structure set out in the Moscito Byte 1.0 system card for the Bermuda Championships (but not included in MB 1.0's code, given time limitations): responder can now show hands with 5+C and 5+D. The response structure to MB 1.0's 2m openings (a good 10 to a bad 15 HCP, with 6-9RP, either a single-suited hand with six or more cards or five plus cards and exactly four cards in the other minor; it denies a four-card or longer major) is derived from Jeff Rubens' TSAR (www.bridgeworld.com/TSAR.html). It differs in a number of respects, reflecting its use over an opening bid (i.e. responder has a much larger number of possible hands) and the need to include a comprehensive relay structure. This relay structure is significantly different from the normal Symmetric structure. This is because it designed to enable intelligent bidding of as many invitational hands as possible. This, together with being designed for use by a computer program, makes the structure memory-intensive for humans. (It is not random, however, following general Symmetric principles such as showing higher shortages before lower shortages wherever possible.) One important, unresolved design issue is whether it is better to have (semi-) natural responses to the first relay or to switch responses so that the likelihood that opener, whose hand is being described, is minimised. My instinctive reaction is that responses should be artificial. I hope that testing with MB 1.0 (and later versions) will enable a statistically valid answer to this question. Notes: 1. Because of the difficulty in programming GIB to determine when to relay and when to respond 3M naturally with GF values, Alan Jaffray changed the following responses: over 2C, 3D-3S all show GF, 4+C, SPL in S/D/H; over 2D, 3C shows 5 good or 6+H with constructive-INV values and 3M/4C show GF, 4+D, SPL in C/H/S. There also some minor changes to the relay structure and to relay followups: 3M are natural and GF when not an INV raise of opener's fragment. 2. The resolution of shapes is slightly different from that in BY's system notes (in particular, I do not want to force RR to bid past 3N to show a 7330 shape when lacking extra strength). 3. I have assumed that the options available to relayer (R) after responder to relay (RR)'s shape is resolved are more clearly defined than in BY's notes and structured slightly differently. In particular, I assume that R can make a natural, NF slam try in all suits, and that this try is based on needing help in the trump suit. 4. In showing responder's shapes in response to 1N, general Symmetric rules have been followed as much as possible (so, for three-suited hands with two known suits, the first step shows that the third suit is the higher-ranking of the two remaining suits). 5. The way shortages are shown is designed to follow the S/H/D/C feature-showing order but with the important caveat that, wherever possible, the shortage is not bid. This is designed to minimise the opportunities for a cheap double by the opponents. 6. Continuations after interference over 1N or 2m are not discussed. MB 1.0 uses a slightly simplified version of the method found in BY's notes. Nomenclature ------------ 4333 any hand with that shape 4-3-3-3 a hand with four spades and three cards in every other suit anti-SPL anti splinter, a suit with honour strength that would be partially or wholly wasted opposite a SPL cm/cM corresponding minor/major, i.e. C&H and S&D F forcing GF game forcing Hxx(x) honour-third (fourth), where an honour is ace, king or queen HS high shortage (order by rank, i.e. S,H,D,C) INV invitational M major m minor max (for 2m opening) 13-15HCP and 7-9RP min (for 2m opening) 10-13HCP and 6-8RP NF non forcing NS new suit Om/OM other minor/major Q cue bid R relayer RKC Roman key-card Blackwood RP relay point(s), A=3, K=2, Q=1, subtracting 1 for singleton honours RR responder to relays SPL splinter TFR transfer 1N opening ---------- 1N shows (11)12-14(15) HCP and 6-9RP (all 10 RP hands are opened 1C and many 15 HCP hands with <10RP are opened 1N). Hands are upgraded and downgraded after comparing the raw HCP with GIB's evaluation metric. Opener's possible shapes are 4M333, 4432/4333 without 4M or 5m332/5m4Om22 (although 6m322 hands can also be accommodated). Responses 2C Stayman, may be to play in 3m 2D/2H TFRs, may be INV with 4M, else 5+M 2S One of: -- 4H+4S INV -- both m, weak (usually at least 55) -- three suiter with 4H+4S, GF+ 2N INV, <4M. Now 3C shows 44m, 3D is to play (usually with 5D) and 3M shows a stopper, worried about OM, max 3C GF, 5+C and 5+D or three suiter with both m and 4M, GF 3D Stopper ask in M. 3M 5+M, GF+, wants to be declarer. If 6+M then slam INV needing 1+/top3. 4m TFR to cM. Later 4S/4N is RKC and NS KC voidwood (4N=void in S after TFR to H) 4M To play 4N Blackwood In all shortage-showing auctions, a bid of the short suit, by either partner, shows general slam interest. Bidding a suit below game sets that suit (if partner has promised 4+ cards there) and is consistent with slam interest. Jumping to game when a below game forcing bid in the same strain is available shows slam interest with good trumps. Stayman 1N 2C 2D 2H relay 2S 5+D or 3-3-4-3 2N 2-3-4-4 (3D) or 3-2-4-4 (3H-3N, i.e. 6-7, 8, 9RP) 3C 3-3-3-4 (3H) or 3-3-2-5 (3S/3N, i.e. 8-9RP/6-7RP) 3D 2-3-3-5 3H 3-2-3-5 3S/3N 2-2-4-5 (i.e. 8-9RP/6-7RP) 2S 5S (or 6 weak S), INV P Min, 2-3S. With a min opener and 2S opener can pass or bid 2N 2N min, usually <3S. Now 3m is good 4-5 card suit 3C inquiry (doesn't promise S support) 3D C SPL or H SPL. Opener bids 3H to ask 3H D SPL 3S 6 very weak S 3N 5S332 or 5S4m22 or 6S322, willing to play in 3N 4S 6S 3D/3H values, S support 3S C values, S support 3N/4S to play 2N Puppet to 3C P to play 3D 5+m, SPL Om (3H asks: 3S D SPL; 3N C SPL, NF; 4C C SPL, slam INV; 4D 6+D, C void) 3M SPL OM, 5+C, GF+ 3N mild slam INV, 5-6C, no SPL 4C-4N 6-7C, no SPL, slam INV, Q bids, needing C support (else relay) 3C TFR->D P to play 3M SPL OM, 5+D, GF+ 3N mild slam INV, 5-6D, no SPL 4C-4N 6-7D, no SPL, slam INV, Q bids, needing D support (else relay) 3D Stopper ask in m. Opener bids: 3H no stop in D (3S asks for stop in C) 3S stop in D, no stop in C 3N stop in both m 3M 5+OM, 4+M, GF+ (3S, then 4S over 3N is 55M with mild slam interest; 3H, then 4H over 3N is GF 55, no slam interest; with strong slam interest, choose the weaker major and then jump to 5m to show a SPL) 3N/4OM to play 3S shape inquiry, slam interest Responder bids 3N HS 4C 5-4-2-2 4D 5-4-3-1 or 5-4-4-0 4H 5+S, 5+H, no slam interest 4S 6-4-2-1 or 6-4-3-0 (and slam interest, else 4S over 2D) 4N 6-4-3-0 or 6-4-2-1 (too strong to risk playing in 4S) 5C+ 5+S, 5+H, strong slam interest, Q (5C shows void etc) 4m Q, slam interest 4m RKC in bid suit 4M To play 1N 2C 2H 2S 5S (or 6 weak S), INV P Min, 2-3S. With a min opener and 2S opener can pass or bid 2N 2N min, usually <3S. Now 3m is good 4-5 card suit 3C inquiry (doesn't promise S support) 3D C SPL or H SPL. Opener bids 3H to ask 3H D SPL 3S 6 very weak S 3N 5S332 or 5S4m22 or 6S322, willing to play in 3N 4S 6S 3D/3H values, S support 3S C values, S support 3N/4S to play 2N Puppet to 3C P to play 3D 5+m, SPL Om, GF+ (3H asks: 3S D SPL; 3N C SPL, NF; 4C C SPL, slam INV; 4D 6+D, C void) 3M SPL OM, 5+C, GF+ 3N mild slam INV, 5-6C, no SPL 4C 2-4-2-5, slam INV 4D 4H, S SPL, 5+C, slam INV 4H 4H, D SPL, 5+C, slam INV, NF 4S 4H, D SPL, 5+C, slam INV, F 4N 6-7C, no SPL, slam INV, needing C support (else relay) 3C TFR->D P to play 3M SPL OM, 5+D, GF+ 3N mild slam INV, 5-6D, no SPL 4C 4H, S SPL, 5+D, slam INV 4D 2-4-5-2, slam INV 4H 4H, C SPL, 5+D, slam INV, NF 4S 4H, C SPL, 5+D, slam INV, F 4N 6-7D, no SPL, slam INV, needing D support (else relay) 3D Stopper ask in m. Opener bids: 3H no stop in D (3S asks for stop in C) 3S stop in D, no stop in C 3N stop in both m 3H Slam INV with at least 54 in H+S 3S shape inquiry 3N 5+H, 4+S. Opener can ask again with 4C 4C 5-4-2-2 or 4-5-2-2. 4D asks 4D 5+S, 4H, C SPL 4H 5+S, 4H, D SPL, NF 4S+ 5+S, 4H, D SPL 4m Q, slam interest 3S Relay (for RP as opener is known to be 3-4-3-3) 4m RKC in bid suit 4H To play 4S RKC in H 1N 2C 2S 2N Puppet to 3C P to play 3D 5+m, SPL Om (3H asks: 3S D SPL; 3N C SPL, NF; 4C C SPL, slam INV; 4D 6+D, C void) 3M SPL OM, 5+C, GF+ 3N mild slam INV, 5-6C, no SPL 4C 4-2-2-5, slam INV 4D 4S, H SPL, 5+C, slam INV 4H 4S, D SPL, 5+C, slam INV 4S 4-2-2-5, slam INV, good S 4N 6-7C, no SPL, slam INV, needing C support (else relay) 3C TFR->D P to play 3M SPL OM, 5+D, GF+ 3N mild slam INV, 5-6D, no SPL 4C 4S, H SPL, 5+D, slam INV 4D 4-2-5-2, slam INV 4H 4S, C SPL, 5+D, slam INV 4S 4-2-5-2, slam INV, good S 4N 6-7D, no SPL, slam INV, needing D support (else relay) 3D Stopper ask in m. Opener bids: 3H no stop in D (3S asks for stop in C) 3S stop in D, no stop in C 3N stop in both m 3H Slam INV with at least 54 in H+S 3S shape inquiry 3N 5+H, 4+S. Opener can ask again with 4C 4C 5-4-2-2 or 4-5-2-2. 4D asks 4D 5+S, 4H, C SPL 4H 5+S, 4H, D SPL, NF 4S+ 5+S, 4H, D SPL 4m Q, slam interest 3S Relay (for RP as opener is known to be 4-3-3-3) 4m RKC in bid suit 4M To play 4N RKC in S Transfers 1N 2D 2H normal 2S/2N(=D)/3C super-accept with 4H, anti-SPL. 3D reTFR. Now 3S=4D (usually 2-5-4-2 or stiff A/K), 3N=4C, 4m=5-card suit 3H asks for Qs 3S SPL in D 3N to play 4C SPL in S 4D SPL in C 1N 2D 2H 2S INV, 5 or 6 weak H. Opener bids 2N min, usually <3H. Now 3m is good 4-5 card suit 3C inquiry (doesn't promise H support) 3D S SPL or C SPL. Opener bids 3H to ask or 3S to show 4S 3H D SPL 3S 4-5-2-2 3N 5332 or 5H4m22 or 6H322 3D values, H support 3H/3N/4H to play 2N INV, 4H. Opener bids 3C inquiry (doesn't promise H support) 3D S SPL or C SPL. Opener bids 3H to ask 3H D SPL 3S 2-4-5-2 3N 4H4m32 or 2-4-2-5 3D values, worry about S stop 3H/3N/4H to play 3C 5+H, 4m. Opener bids 3D relay (usual bid) 3H S SPL or 5H4m22 3S D SPL 3N C SPL, no slam interest 4C C SPL, slam interest 4D 6H+4D, slam INV, control in both S and C 4H 6H+4C, slam INV, control in both S and D 4S 0-5-4-4, slam INV 3H 3-4H, spread-out values 3S 5H4m22, slam interest 3N S SPL, slam interest 4C D SPL, slam interest 4D C SPL, slam interest 4H no slam interest 3S/4m 3-4H, anti-SPL 3N 2H, 1.5+ stops in all other suits 3D 6+H, INV+ (or 5332 with small doubleton and strong H). May be slam INV with singleton. Opener bids 3H Rejecting INV 3S/4m SPL in D/S/C, slam try, good suit 3N COG 3S/4m Accepting INV, anti-SPL 3N Offer of game, H honour and stoppers in all suits 3H 5+H and 5+C 3S H support, good slam cards 3N to play, usually misfit 4C C support, good slam cards 4H/5C support, bad slam cards 4D/4S Q, C support 4N C support, good slam cards, no A in D or S (i.e. good cards in H and C) 3S 5+H and 5+D 3N to play, usually misfit 4C H support, good slam cards 4D D support, good slam cards 4H/5D support, bad slam cards 4S/5C Q, D support, Q 4N D support, good slam cards, no A in C or S (i.e. good cards in H and D) 3N COG, usually 5332 or 5H4m22 with values in doubletons Opener Qs with max if converting to 4H in case responder has mild slam INV 4m void in S/C, 6+H, slam INV 4H mild slam INV, 6+H no SPL or stiff A/K 4N slam INV, 5H332, weak H 1N 2H 2S normal 2N(=H)/3m super-accept with 4S, anti-SPL. 3H reTFR. Now 3N=4D (usually 5-2-4-2 or stiff A/K), 4C=4C, 4D/4H(=C)=5-card suit 3S asks for Qs 3N to play 4C SPL in H 4D SPL in C 4H SPL in D 1N 2H 2S 2N INV, 4S. Opener bids 3C inquiry (doesn't promise S support) 3D H SPL or C SPL. Opener bids 3H to ask 3H D SPL 3S 4-2-5-2 3N 4432 or 4-2-2-5 3D values, worry about S stop 3S/3N/4S to play 3C 5+S, 4m. Opener bids 3D relay (usual bid) 3H C SPL or 5S4m22 3S D SPL 3N H SPL, no slam interest 4C H SPL, slam interest 4D 6S+4D, slam INV, control in both H and C 4H 6S+4C, slam INV, control in both H and D 4S 5-0-4-4, slam INV 3S 3-4S, spread-out values 3N 5S4m22, slam interest 4C H SPL, slam interest 4D C SPL, slam interest 4H D SPL, slam interest 4S no slam interest 3H/4m 3-4S, anti-SPL 3N 2S, 1.5+ stops in all other suits 3D 6+S, INV+ (or 5332 with small doubleton and strong S). May be slam INV with singleton. Opener bids 3S Rejecting INV 4m/4H SPL in H/C/D, slam try, good suit 3N COG 3H/4m Accepting INV, anti-SPL 3N Offer of game, S honour and stoppers in all suits 3H 5+S and 5+C 3S S support, good slam cards 3N to play, usually misfit 4C C support, good slam cards 4S/5C support, bad slam cards 4D/4H Q, C support 4N C support, good slam cards, no A in D or H (i.e. good cards in S and C) 3S 5+S and 5+D 3N to play, usually misfit 4C S support, good slam cards 4D D support, good slam cards 4S/5D support, bad slam cards 4H/5C Q, D support, Q 4N D support, good slam cards, no A in C or H (i.e. good cards in S and D) 3N COG, usually 5332 or 5S4m22 with values in doubletons Opener Qs with max if converting to 4S in case responder has mild slam INV 4m/4H void in H/C/D, 6+S, slam INV 4S mild slam INV, 6+S no SPL or stiff A/K 4N slam INV, 5S332, weak S Interference after 1N P 2D/2H: XX Good 5-card or very good 4-card suit, suggesting a place to play P 2-card support 2M (accept TFR) 3-card support NS/2N max, anti-SPL, 4 trumps 3M min, 4 trumps Other sequences 1N 2S 2N to play opposite 4H+4S INV P 4H+4S INV 3C both m, weak 3D three suiter with 4+D, GF+ 3H 4-4-1-4, GF+ 3S 4-4-0-5, GF+ 3m preference, wanting to play in 3/4M or 3N opposite 4H+4S INV 3H 4H+4S INV 3S three suiter with 4H+4S, GF, long in D 3N three suiter with 4H+4S, GF, long in C 4C 4-4-1-4, slam INV 4D 4-4-0-5, slam INV Interference after 1N P 2S: XX to play X (by opener of 3m) penalties X (by responder) penalties of M, takeout of m 1N 3C 3D 3H 5+C and 5+D 3S relay (3N HS, 4C 1-1-5-6 or 1-1-6-5, 4D 2-1-5-5, 4H 3-0-5-5, 4S 2-0-5-6, 4N 2-0-6-5 better than min, 5C 2-0-6-5 min GF, 5D+ 2-0-6-5 slam force, Q) 3N to play 4m good trumps (HJxx or better), responder Qs with better than min 3S three suiter short in H, GF+ 4m natural 4H slam interest in S 3N three suiter short in S, GF 4m 0-4-5m4Om, slam interest 4H 1-4-4-4, slam interest, NF 4S 1-4-4-4, strong slam interest Interference after 1N P 3C: XX to play X penalties of m, takeout of M (by responder)/penalties of M by opener NS forcing 1N 3D 3H no stop in S (3S asks for stop in H) 3S stop in S, no stop in H 3N stop in both M Interference after 1N P 3D: XX to play X penalties NS forcing 1N 3M 3N 2-card support (Now NS is suit above SPL) NS max, anti-SPL, Hxx or better in trumps 4M min, 3-4 trumps Interference after 1N P 3M: XX looking for penalties P <3M X penalties 3N offer of contract with 3-card support NS max, anti-SPL, Hxx or better in trumps 4M min, 3-4 trumps Relays Usual relay rules apply with following modifications: -- non-step bids below 3N when shape not resolved are stopper asks (usual S/H/D/C order but swap as necessary so R never bids a suit to ask in it) -- when shape is resolved at 3S/3N, opener shows his strength so some modification of usual rules (R will not have a short-suit slam try, and hands wanting to use RKC will be infrequent so all NF slam tries are trump help slam tries, even in 2-3 card suits) 4C asks for RP 4D forces 4H, to play in game or 4N quantitative slam INV 4M/5m NF trump help slam try, asking for good trumps 4N RKC in longest highest-ranking suit Trump help slam try (help ST) This natural, NF slam try asks for extra strength in the trump suit. The trump fit is usually exactly 8 cards. If RR has a 4-5 card suit, R denies two honours in the suit; a typical holding is Hxxx, so RR needs KJxx(x) or better to accept. With a 2-3 card suit, RR needs 1+/top3 to accept. Accepting a slam try If accepting a trump help ST, RR bids Step Strong trumps, 9RP Step+1 Strong trumps, 8RP Step+2 Strong trumps, 7RP Step+3 Strong trumps, 6RP 2C opening ---------- 10-15HCP, 6-9RP, 5+C, <5D, <4M. 1N is an option with 2-2-4-5 when C are weak. Responses 2D relay, either GF or INV with at least Hx in C 2M (very good 5) 6+M, constructive-INV. 2N and 3C are natural and encouraging. OM and 3D show fragments with 3-card support 3M suggests 3M6C22 or doubleton support (Hx or better), better than min JOM and 4D are fragments with 3-card support, promising a void 3N max, solid 6+C 4C max, 8+C 4M max, 3M6C22 2N INV, misfit (usually singleton C; if doubleton, then 5C with max) 3S anti-relay, asking for max (3N min, 4C 1-3-4-5 max, 4D-5C 0-3-4-6 max) 3H 1-3-3-6 3S 0-3-3-7 3N 1-3-2-7, min 4C 8+C (4H void, Z->5C with singleton) 4D-5C 1-3-2-7, max, Z 3D natural 3H 3D, or 4D min 3S 1-3-4-5 max 3N 1-3-2-7 4C 0-3-4-6 max 3C 6+SS C 3D relay 3H S SPL (3N 1-3-3-6, 4C 0-3-4-6, 4D 0-3-3-7, 4H-5C 1-3-2-7) 3S 2-3-2-6 3N 3-3-1-6 4C 3-3-0-7 4D-5C 2-3-1-7 3D 2-3-2-6 3H 3-3-1-6 3S 3-3-0-7 3N 2-3-1-7, min 4C 8+C (void 4H, Z->5C with singleton) 4D-5C 2-3-1-7, max 2N INV 3C INV 3D Stopper ask 3H no stop in S (3S asks for stopper in D) 3S stop in S, no stop in D 3N stops in both 4C 8-card suit 3H INV 3S D SPL, 4+C 4m SPL raise of H in S/C 2S 3-card S, denies 3H 2N relay 3C short D, 3-2-2-6 (3H), 3-1-2-7 (3S), 3-2-1-7 (3N/4D-5C min/max) or 8+C (4C) 3D 6+SS C 3H relay 3S 3-2-2-6 3N 3-0-4-6 4C 3-1-2-7 4D 3-0-3-7 4H-5C 3-2-1-7 3H 3-1-4-5 3S 3-0-4-6 3N 3-0-3-7, min 4C 8+C (4H void, Z->5C with singleton) 4D-5C 3-0-3-7, max 3C INV 3D Stopper ask 3H no stop in H (3S asks for stopper in D) 3S stop in H, no stop in D 3N stops in both 4C 8-card suit 3H D SPL, 4+C 3S INV 4m/4H SPL raise of S (H/C/D) 2N 2-2-4-5, 2-2-3-6 or 2-2-2-7 3C INV 3D Stopper ask 3H no stop in S 3S stop in S, no stop in H 3N stops in both 3H relay 3S 2-2-4-5 3N 2-2-3-6 or 2-2-2-7, min 4C 2-2-3-6, max 4D 2-2-3-6 (4S) or 2-2-2-7 (4N+), SS max 4H-5C 2-2-2-7, max 3S D SPL, 4+C 3C 1-2, 2-1, 0-2, 2-0 or 1-1 M, 6+C, min P INV 3D relay 3H D SPL, 4+C 3D 1-2 or 2-1M, 6+SS C 3H relay 3S H SPL 3N 1-2-4-6 4C+ 1-2-3-7 3S anti-relay 3N S SPL 4C 1-2-4-6 4D+ 1-2-3-7 3H max, 1-2-4-6 (3N), 1-2-3-7 (4D+) or 0-2-4-7 (4C) 3S 2-1-4-6, max 3N 2-1-3-7, max 4C 1-1-4-7, max 4D 8+C (4S S SPL, 4N H SPL, 5C D SPL) 4H-5C 2-0-4-7, max 2D opening ---------- Responses 2H relay, either GF or INV with at least Hx in D 2S (very good 5) 6+S, constructive-INV. 2N and 3D are natural and encouraging. 3C/3H fragments with 3-card support 3S suggests 3-2-6-2 or doubleton support (Qx) and a max 3N max, 6+ solid D, <3S 4C/4H fragments with 3-card support, promising a void 4D max, 8+D 4S max with 3-2-6-2 (or stiff A or K, not wanting to show fragment) 2N INV, misfit (usually singleton D; if doubleton,