## Saturday, May 15, 2010

### Re-Thinking 4SF

I was asked to think about 4SF sequences.  The question was whether this should best be GF or forcing to 2NT, or something else.  I realize that most people define all 4SF sequences the same.  But, this did not seem to make sense to me, as each is different.  My suggestion in response to the proposed question is still in discussion, but you may find this worth considering, as well.

For sake of discussion, I have assumed that the 4SF sequences we are concerned about are those with a one-over-one response, no reverse by Opener. The following sequences are the entirety of the qualifying sequences:

1. 1♣ - 1 - 1 - 1♠ (and what is 2♠?)
2. 1♣ - 1 - 1♠ - 2
3. 1♣ - 1 - 1♠ - 2
4. 1 - 1 - 1♠ - 2♣
5. 1 - 1 - 2♣ - 2♠
6. 1 - 1♠ - 2♣ - 2
7. 1 - 1♠ - 2♣ - 2
8. 1 - 1♠ - 2 - 3♣

This set need not all be handled the same, as each has somewhat of a unique set of parameters. However, some consistency makes sense.

Two of these sequence have a unique similarity:

4. 1 - 1 - 1♠ - 2♣
7. 1 - 1♠ - 2♣ - 2

In these two sequences, the 4SF call is below two of Opener’s long suit and is below two of Responder’s first suit. In both of these, Opener can:

1. rebid his long suit with a minimum and no fit for Responder’s suit,
2. can bid two of Responder’s suit with a minimum and a fit for Responder’s suit,
3. can bid 2NT with a maximum and a fit, or
4. can bid anything else (logical) with a maximum and no fit.

If we use that approach, then I think these two sequences should be invitational or better. If Opener shows a minimum, with or without a fit, the Responder can:

1. pass or
2. bid 2NT to play, but
3. any other call is GF.

One sequence is nearly identical, in theory:

3. 1♣ - 1 - 1♠ - 2

In this sequence, Opener could:

1. rebid his shorter suit (2) with a minimum and no fit,
2. bid 2♠ with fit and a minimum,
3. 2NT with a maximum and a fit, or
4. any other with a maximum and no fit (logical).

This would allow the same basic approach, with Responder bidding

1. pass, or
2. correcting 2 to 3♣ as NF, or
3. bidding 2NT to play, or
4. any other call as GF.

In all other situations, excepting the weird 1-1-1-1 sequence, I think 4SGF is probably the best approach, because of the space concerns.

Thus, this type of analysis would lead me to a conclusion:

1. Fourth Suit is Forcing to Game if the Fourth Suit is a major OR is 3♣.

2. Fourth Suit is Invitational+ if the Fourth Suit is a MINOR at the TWO-LEVEL.

a. If 4SF is a MINOR at the TWO-LEVEL, Opener can:
i. Bid Responder’s major at the two-level with a 3-fit* and a minimum
ii. Bid his own cheapest suit at the two-level with no fit and a minimum (this will always be the “relay,” the next-suit-up)
iii. Bid 2NT as an artificial bid showing a maximum with a 3-fit for Responder’s suit (GF)
iv. Any other call is GF and logical

b. If Opener shows a minimum, with or without fit, then:
i. Responder can pass Opener’s call
ii. Responder can correct to Opener’s long suit to play
iii. Responder can bid 2NT to play
iv. Any other call is GF

*We might tweak this such that Opener’s “minimum with 3-fit” is actually “minimum with 2-3 cards in fit.” The “non-fit minimum” option would then be 0-1 in Responder’s suit. This might make sense if unbalanced 3-fit raises would be common.

Special Case of 1♣ - 1 - 1 - 1♠ or 1♣ - 1 - 1 - 2♠:

I like the latter (1♣-1-1-2♠) as GF with the true 4♠/5+hand.

The former (1♣-1-1-1♠) maybe should be 4SF, with 1♠ artificial. Probably just a one-round force, actually. If Responder runs into a problem, he can always rebid 2♠, which cannot be natural (because he did not bid 2♠ the first time).

Suppose 1♣-1-1-1♠ start, and Opener rebids 2♣. If Responder bids 2♠, this is clearly forcing, again, because Responder could have jumped to 2♠ over 1. So, 1♠ as a one-round force only is not a real problem. We could stop at 1NT, even.

[This, howevetr, is also where I have consiodered a one-level "Kokish" style of auction...]