[mgoetze]

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Here is what Swan 4.0 has to say about handling 1-level interference

Quote

Pass: No wish to compete at the moment or unwilling to commit to game if OP should be strong. Later voluntary actions are balancing, and a later voluntary bid in the suit of an overcall is NAT, NF.

RDBL: General positive, 11+ hp, usually BAL. F-1NT or PEN.
OP passes only with club length, else rebids NAT. 2 is ART FG - also from RP.

1R and DBL of 1R: TRF, at least 4-c M (next suit), 8+ hcp. But if 1R was TRF, promising 5-c relay suit (or 4-c with about 10+ hcp), DBL shows the suit bid.
[...]

1♠ and DBL of 1♠: T/O, denies 4-c suits higher than the overcalled suit. (Over 1, 4-c hearts is possible, and an ART overcalled suit may also be possible as trumps.)
Weak OP usually rebids 1NT (does not promise a stopper), but may choose to rebid 2m with a 5-c suit.
RP’s CUE in OPP’s genuine suit or bid in a suit he has denied asks for a stopper. Otherwise RP’s rebids in m are NF, but rebids in M are F1 with a 4-c suit. RP may bid 1♠ followed by a rebid in clubs in order not to wrong-side NT.
Strong OP rebids something else - e.g. 2NT (2NT methods apply) or CUE (usually BAL without a stopper). A rebid in 2nd hand’s suit is NAT.

1NT/2X: TRF. TRF to a lower-ranking suit may be just competitive. Weak OP may show support by a ”jump” to the 3-level.
If TRF could have been made at the 1-level, a 2-level TRF promises 6-c suit and INV+ values.
Over an INV+ TRF to M, a weak OP bids 2M (NF), 3M (FG, leaving room for slam tries) or 4M (only when single jump after further competition), so new suit (NAT, also in the suit bid by 2nd hand) and 2NT show the strong type.
After TRF to 2X and OP’s 2NT, RP’s bids below 3X are TRF, 3X shows (extra) clubs, and bids above X are NAT. (Exception: RP’s TRF to - or a bid in - the suit of a NAT overcall shows extra values without extra lengths.) RP’s 4m is a ”retransfer” to 4M with MIN but a very good suit.
Over 2♠ (TRF to clubs, INV+), a weak OP bids 2NT (stopper, F1, may also be strong), 3♣ (no stopper, not MAX) or CUE (no stopper, MAX but not FG).
CUE may also be strong without a stopper.
TRF to OPP’s ”genuine” suit (5-c or 4-c with about 10+ hcp) is INV with at least 4-5 in the highest unbid M and a minor. Weak OP may pass 2 or 2, give preference to m by 3 (P/C) or bid NT / RP’s M quantatively. Accept of TRF is ART, either weak OP with game interest or strong. Other rebids are NAT, strong.
TRF to OPP’s ”non-genuine” suit promises that suit.
RP’s rebid in a new suit is NAT F1; raises and bids in NT are NAT INV. A CUE is primarily asking for a stopper; a jump in new suit is SPL.

2NT: 5-5 m. Weak OP bids 3m or 5m (rarely, unless over 4M). A jump to 4m is strong.

3Y: Single jump: INV with good 6-c suit. This includes 3X after ART 1X.
Double jump: Sound PRE with 7-c suit.

3X: (When OPP have shown ”genuine” X): Asking for a stopper, long m.

4m: TRF to 4M (even if OPP’s suit). OP’s relay is strong, and CTL may follow.
OP’s 4NT is RKCB.

After reading all that, I'm still not sure whether I'm supposed to pass, double, or bid 2♦ on the hand given above.

[the hog]

The quoted text is quite clear that this is a double.

[DinDIP]

I presume the rationale for playing 1N+ as TFRs is so there is commonality with auctions after two-level overcalls. But I think that's wrong. A natural, limited 1N is too valuable to give up for any TFR method, and space is not at a premium as it is when they overcall 2M. Partner and I play (after our strong-only club) that 1N is NAT, NF and 2C-2S are TFRs to the next suit or, if a TFR to their suit, a BALish hand without a stopper. There is some loss of space when responder has long clubs but the gains from being able to TFR into the other suits and show a NAT limited hand with a stopper outweigh that loss. I think the gains even greater when playing a two-way 1C opening when 1N is an even more likely contract, and especially as you really want to be able to show a BAL 8-11 with a stopper when opener is strong.

David

[mgoetze]

DinDIP, on 2012-March-21, 17:33, said:

I presume the rationale for playing 1N+ as TFRs is so there is commonality with auctions after two-level overcalls.

I think it is more because opposite the 11-13 balanced hand it is common to have both hands where you just want to play 2x and hands where you want to go to game, and it seems wasteful to bid at the 3-level with the latter. Also, opener now has an easy time showing whether he has 11-13 balanced (complete the transfer) or a strong hand (do anything else).

[Cthulhu D]

I think you have to double. I'm not sure 2D showing hearts is great, particularly as double here should probably imply 4 hearts anyway, so 2D should show a hand more like a NFB, or something stronger.

[DinDIP]

DinDIP said:

I presume the rationale for playing 1N+ as TFRs is so there is commonality with auctions after two-level overcalls.

mgoetze, on 2012-March-21, 17:43, said:

I think it is more because opposite the 11-13 balanced hand it is common to have both hands where you just want to play 2x and hands where you want to go to game, and it seems wasteful to bid at the 3-level with the latter. Also, opener now has an easy time showing whether he has 11-13 balanced (complete the transfer) or a strong hand (do anything else).

I agree that's the rationale for TFRs but my point is that the first TFR doesn't need to be 1N. The situation after a one-level overcall is different to that after a 2M overcall, where space is at a premium and it is a favourable tradeoff on balance for TFRs to start with 2N. In my experience a NAT, NF 1N is too valuable a bid to give up. This is true if opener's hand is 11-13 BAL. And it's even more true when opener has some 17+ hand.

1N isn't the only option with the problem hand (KT63 A982 9843 K) -- maybe a takeout X is better to show the four-card H suit. But change responder's hand to something like KT6 A98 9843 K32 and 1N is clearcut. If you are forced to pass with hands like this you make it impossible for our side to declare 1N -- a typically advantagous contract at all forms of scoring -- when opener is minimum and BAL. And you put serious pressure on opener whenever he has a strong hand. Should he reopen with xxx KQx AKJx KJx or the like if you pass 1S? I think opener has to be able to assume that responder will have acted over 1S on virtually all hands with sufficient strength to force to game opposite 17+. (Note that this is not true when the overcall is 2M, which is why getting to the two level before the 1C opener has the opportunity to clarify his strength and shape is so important.)

David

[gwnn]

Does the text really say something about transferring into 4-card suits? That would be pretty ugly. Transfers are cool but not if it can be 4-7 cards long!

[mgoetze]

gwnn, on 2012-March-22, 16:07, said:

Does the text really say something about transferring into 4-card suits? That would be pretty ugly. Transfers are cool but not if it can be 4-7 cards long!

I thought you've read it? Anyway it only mentions 4-card suits for one-level transfers. But it isn't explicit about the length required for 2-level transfers. I would agree that 5+ makes sense.