Seismic 1M Structure

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The Seismic Club major structure covers responses of 2M or higher to an opening bid of 1M, showing 8-15 HCP and a 5-card major.  For bids of 1 over 1,  2 over 1, or 1NT, 2, or 2 over either major, you can use any approach you want.  Currently I'm using these bids analogous to the 2/1 system, with the necessary adjustments for light openings.  These bids can also be standard-like, or even 2/1-Non-Forcing. 

For bids of 2M and above, we use the following systems:

Direct Raises:

2M: This is a "normal" raise, showing at least (probably exactly) 3-card support and about 7-10 points.  With a maximal 1M hand, opener can continue bidding using whatever game-try methods are preferred.

3M: As we will see below, the invitational raise is done using compressed Bergen raises.  The 3M bid is then freed up to be a preemptive raise, showing at least 4-card support and 0-6 HCP.

4M: To play. This is either preemptive or intending to make without slam interest.  Let the opponents figure out if they want to try anything here.

Compressed Bergen Raises:

The normal Bergen raises of 3 or 3 over 1M are used to show 4-card raises of a major with constructive (7-10) or  invitational (10-12) points, respectively.  In Seismic, we combine these point ranges and assign them to a single bid, 3M-2.  Thus, the compressed Bergen raises are 1-3, and 1-3.  In addition to these two hand types, we add into these bids all strong splinters (4+ support, 17-19 points) and balanced hands with exactly 3-card support, no other 4-card major, and 18-20 points.  Usually when this bid comes up, it will be a compressed Bergen raise.

After responder makes this bid, opener assumes that this is a compressed Bergen raise and makes one of two bids.  With a hand that intends to accept an invitational bid, opener bids the next step (3 over , 3 over ).  With a hand that would decline the invitation, opener rebids his major at the 3-level.  If opener has an absolute max, he can also bid 4M directly, knowing that responder may have as few as 7 points.

Once opener has made this choice, responder acts according to his hand type.

  • With a constructive Bergen raise, responder passes 3M or bids 3M over opener's acceptance of 3M-1. 

  • With an invitational Bergen raise, responder passes 3M, or bids 4M over opener's acceptance of 3M-1.

  • With a strong splinter, responder bids his singleton or void cheaply.

  • With a strong balanced hand, responder bids 3NT.

If responder does not sign off, but instead shows the strong splinter or strong balanced hand, opener can explore for slam, or sign off in 4M (or pass 3NT).

Limit Raise with Shortness (Weak Splinter):

A bid of 3M-1 (1-3 or 1-3H) shows a hand with 4-card support and shortness in a side suit.  Responder's values are barely GF (would not be GF without distribution) and shows no interest in slam unless opener has a great maximum.  Opener will typically sign off in game, leaving the shortness unknown.  With a great maximum and slam aspirations, opener bids 3M (note, here 3M is strong) to inquire about the shortness.

To answer the shortness query, responder bids the next step (3M+1) to show a void.  The next 3 bids, (3M+2 through 3M+4 = 4M-1) show a singleton in the bid suit, or in the obvious unavailable suit if the bid is NT.  For example, 1-3-3-3NT, shows a singleton .  If responder bids 3M+1 to show a void, opener puppets to 3M+2 to inquire the void's location.  This question is answered similarly, with 4M showing a void in the unavailable suit.  For example 1-3-3-3-3NT-4 shows a void.

Once the location and degree of shortness are known, opener can sign off in 4M or continue on toward slam.

Jacoby 2NT / 3:

A response of 2M+2 (1-2NT or 1-3) is a Jacoby bid.  Over 1, this is exactly like a normal Jacoby 2NT, albeit with point ranges modified to account for light openings.  Opener responds as usual:

  • 3NT shows good values (12-15)

  • 3M shows extra length (6+) and strength (12-15, maybe 13-15) without shortness.

  • 4M shows a minimum.

  • Other 3-level bids show shortness in the bid suit.

  • Other 4-level bids show a good 5-card suit (note that this also implies shortness somewhere, so these bids take priority over the 3-level bids)

A single exception to this is that over 1-3 we do not have both 3 and 4 available to show shortness or length in clubs.  Since shortness is more common, we use 4 to show shortness after 1.  Hands with a good side suit bid their shortness instead.

It is a matter of partnership agreement whether the shape-showing bids imply extra strength or are just for shape.

3NT over 1M:

A response of 3NT shows 15-17 points and 33(43) shape.  Game in either 3NT or 4M is reasonable and slam is possible if opener has a maximum.

Compressed Jump-Shifts:

Compressed Jump-Shifts are another aspect of Seismic that can seem very complicated but actually works very logically.  There are 2 hand types that make this bid.  A very strong (more than GF values) hand with a self-sufficient (or nearly so) 6+-card suit, or a strong (at least GF) hand with 4-card support and a good 5+-card suit (rarely 5+-card support and a good 4-card suit).  With one of these hand types, opener bids 2M+1 (1-2 or 1-2NT).

Opener puppets to the next step beginning a brief relay sequence in which two questions are asked:

  1. What is your suit?
  2. What type of hand do you have?

To answer the first question, the next two available bids by responder (3, 3 over 1 and 3, 3 over 1) show the suit bid.  Higher bids by responder show the 3rd suit and zoom into answering the 2nd question.  If responder bids one of the first two suits to answer the first question, opener again puppets to the next bid and responder answers the second question.  the rules for this answer are as follows:

  • Bidding opener's suit shows the 2-suited hand with support and denies side shortness.  If 3M is available to answer this question, then both 3M and 4M show this hand type, but 4M shows a minimum and 3M shows extras.  This will happen unless responder has the "middle" suit of the possibilities.

  • Bidding/rebidding responder's known suit shows a single-suited hand and a non-solid suit.

  • Bidding 3NT shows a single-suited hand with a semi-solid suit.

  • Bidding a new suit shows the two-suited hand with support, and also shows shortness in the bid suit.

Once responder's hand is fully described, opener can sign off in game, or explore for slam via ace-asks or cuebids.

Medium Splinters:

The normal splinter bids (1-3/4/4 or 1-4/4/4) show a splinter in the bid suit and limit responder to 14-16 points.

Higher Bids:

Higher bids are "normal" and include 4NT as RKC Blackwood, 5-level bids as exclusion Blackwood, and so on.