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Infernal Machine for Limited Convention Chart


The Infernal Machine is an attack system with 4+card majors 8-10 and a 10-13 NT 1st and 2nd seat as the central defining bids. Together, these three bids are opened in first seat 35% of the time with most of the 8-10 counts being hands that others pass. Something is opened 1st seat 66% of the time. I've had some good luck playing this system (click on my name for other articles about it including links to the full system notes). Jeff Meckstroth, who is on the Competitions and Conventions Committee, mentioned that he thought such a system probably should not be permitted in local club games. His best chance to make this happen is to draft me for the C&C committee. Interestingly, the key features of the Infernal Machine and many of the other conventions can be played in restricted games. As a thought experiment, I am offering a version of the system that can be played in the under-20 masterpoint games. 

Limitations of Limited Convention Chart

There are a few relevant differences between the General Convention Chart (most club games) and the Limited Convention Chart (upper masterpoint limit of at most 20). There are some crucial similarities though. Both can be found here:


1 and 2 openings may not be artificial. 

Responses and Rebids

Calls that ask or show aces, kings, queens, singletons, voids or trump quality are permitted in most cases.

A simple response cannot be conventional and game forcing (but can be natural and game forcing) except per above. Jump responses can be natural or raises.

Responses to 15+ bids other than 2 or 1N may not typically be conventional except per above.

Other rebids may not be conventional except per above.


NT for 3-suited takeout is not permitted unless there is a known 4+card suit and at least one 5-card suit.

Infernal Machine for the Limited Convention Chart

Opening Bids 1st/2nd

1 = 10-14 HCP, artificial, can't open anything else, forcing one round.

1 = 15+ HCP, 3+, forcing.

1M = 8-10 HCP, 4+M, with 4+-4+ open 1.

1N = 10-13- HCP and can't open 1M.

2 = 15+ 5+M or 0-2; response: 2 waiting, higher game forcing and natural; rebids: 2M 5+M forcing; 2N = 15-18 Natural 2; 3 = Natural, 0-2 (19+ if natural NT).

2 = 10+-14 5+.

2M = 10+-14 5+M, 0-3 other major, must have a singleton, void or 6-card suit.

2N = 20-21 Natural.

Opening Bids 3rd/4th

1 = 15+ artificial and forcing and can't open anything else.

1 = 3+ 17+ forcing.

1M = 5+M 17+ forcing.

1N = 14-16.

2 of a suit = 5+ card suit 3-14, no conventions in subsequent bidding.

2N = 21-22 Natural.

3N = Gambling.


X of 1 of a suit opening if partner UPH = 15+ natural NT, if partner PH = 17+ natural NT; if a X of 1 also shows a stopper.

A simple suit overcall = can be a 4-card suit if (4441).

1N = 4+ highest unbid major, (54) any two unbid suits, usually 3 in third unbid suit.

Jump overcall of 2 = 5+, 4+.

Jump overcall of 2 = 5+, 4+

Minor Michaels: 5+, 4

Major Michaels: 4+other major, 5+either minor

Positive game forcing doubles after our 1 opener 1st and 2nd followed by a 1 of a suit overcall.

(Weak NT)-2 = any two suiter, weak

Responses and Rebids

Responses to 1 1st/2nd

1 = Asking about voids functioning as a puppet to 1 with responder to pattern via answers artificial asking bids (can't do a responder artificial GF relay because each partner has to describe to avoid being a relay system)

1M = Natural, non-forcing, 0-9 HCP

1N = Natural (whatever that means for a no-trump response), non-focing, 0-9 HCP

2 = void ask with stayman style responses except for 3 showing a void 12-13- (jump with a game force)

2 = void ask with stayman style responses except for 3 showing a void 10-11 (jump with a game force)

2M = Natural, 5+M, 10-11

2N+ = Natural 10-11

Responses to 1 all seats

1 = void ask functioning as a puppet to 1 with responder with game forcing values to pattern via answers to artificial asking bids 

1 = natural negative

1N = natural negative

2+ similar to 1 opener with lower ranges

Responses to 1 1st/2nd

1 = void ask functioning as a transfer to 1NT with opener able to show other suits and responder able to rebid with non-forcing, non-invitational hands or 3+card raises

1N = game forcing natural (whatever that means for a 1NT response). Opener rebids natural or singleton or void showing rebids patterning out.

New suits below 3N = natural invitation.

4m = singleton showing raise.

2/3 = drop dead.

Responses to 1 1st/2nd

1N = Non-forcing natural

2 = void ask functioning as a puppet to 2 with responder to pattern out with game forcing hands

2 = void ask functioning as a puppet to 2 with responder to sign off in any side suit or invite with 3+

new suits below 3N = natural invitation

2/3 = drop dead

1-4m = singleton showing raise.


It may be a bit of a challenge to crimp such a system on the general convention chart given that the essence of it can be played in the 0-20 game. One idea would be to introduce the European Bridge League and World Bridge Federation concepts of "Brown Sticker" conventions. They limit the number of Brown Sticker conventions that may be played in a pair game or a non-super-chart team game. Another would be to limit the asking bids and telling bids to game forcing hands. Another would be to permit 8 and 9 counts to be opened at the one level only in 3rd or 4th seat. Another would be to define relay systems more expansively. Another would be to force opening bid ranges to be the same in all seats. All of these restrictions have drawbacks. Interesting times.


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