Leghorn Diamond System
The system features are:
1C OPENING: artificial, forcing, but not necessarily strong; opener has
The responses: *
1D/2C ... negative: 0-8. 2C shows clubs. *
1H/1S ... 8+ points, Canape IF responder rebids in a different suit. *
1N ...... balanced 8-10 and denies a four card major. *
2D/2H/2S .. natural and game-forcing; 2D may be canape if responder rebids in a major. *
2N ...... balanced 11-12 and denies a four card major. *
3C ...... natural and forcing for one round (inviting 3NT).
Over a double, * there are five negative responses (up to 9 pts): ** pass shows four clubs **
1D, 1H, 1S, and 2C are natural *
with 8-11 and three clubs, responder passes and then makes a "strong" rebid (double, cue bidding, bidding no trump) *
1N ...... 10-11 hcp, any shape *
redouble or jump in a suit shows 12 or more hcp
Over an overcall, *
2C ...... shows 5-7 pts *
1N ...... 10-11, any shape *
cue bid .... asks for a stopper (and is game-forcing) *
new suits .. 8-11 pts at the one level or 12+ at the two level
Opener rebids as naturally as possible. Opener's minimum rebid in a major tends to show a balanced hand
but may be made with a minimum unbalanced hand. With 12-17 opener rebids in a minor; with 16-17, jumps to two of a major; and with 18-20, jumps to the three level in any suit. A jump to 2N after a positive (1H or 1S) shows exactly 15 hcp.
1D OPENING: strong, forcing opening of 19 or more hcp. It may be lighter if opener is within a trick of game. Responder shows controls via steps in the suit bids: 1H (0 controls), 1S (1), 2C (2), 2D (3), etc. The no trump responses show scattered queens and jacks: 1N (5-6 hcp) and 2N (7+ hcp). Over interference pass shows 0 controls, (re)double shows 1 control, etc. Opener rebids in no trump to show a balanced 19-22, jump rebids in no trump to show a balanced 22+, or makes a minimum new suit bid to show an unbalanced hand. Over rebids in no trump, responder uses the same structure as over a direct 1N opening (see below). Over a new suit, responder rebids in steps to show their support. After this response, opener bid another suit to ask for that suit (same steps).
1H or 1S OPENING: natural, but shows either
Opener simply rebids in the major with (a), but rebids a side suit with (b). With 17-19, opener jumps in the
side suit.
1-NT OPENING: balanced 16-18 hcp, denying a five card major. 2C is Stayman. 2D thru 2S are weak transfers to the next suit; the 2S bid is a transfer to clubs, but over this responder can rebid 3D to show long diamonds. Jumps in suits are natural and slam inviting. Jumps to 4D and 4H are Texas transfers.
2C and 2D OPENINGS: same as in Roman system. The 2C opening shows 12-16 with any 4-4-4-1 hand; the 2D opening shows 17-19 with any 4-4-4-1 hand. 2N is a strong inquiry asking for the singleton.
2H and 2S OPENINGS: show five plus card majors and a four or five card minor with 9-12 hcp. 2N by responder asks for the minor. A new suit by responder asks for the full hand pattern: rebid in major .. six card suit rebid in minor .. five card minor 3N .............. 5-4-2-2 new suit ........ three card fragment
2-NT OPENING: five-five in the minors with 14-16 hcp. Jumps to four of a minor ask opener to bid a six card minor or rebid 4H with a minimum or 4S with a maximum. Other responses are to play.
OTHER OPENINGS: Three level preempt: semi-solid seven card suit preempt. 3N: Blackwood. 3N is also Blackwood in other auctions when it cannot be natural.
Defensive bidding: ITALIAN STYLE Doubles show opening hand values with any shape. Overcalls are freely made. With a three suited takeout hand, overcaller cue bids with 12-16 or jump cue bids with 17+ hcp.
EXCEPTION: 2C over a 1C opening shows any 4-4-4-1 hand with 12-16 hcp. Intermediate jump overcalls. 3N over a three level preempt shows two suits of the same rank (majors or minors); double over a three level preempt shows two suits of different rank.