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After 1C 1C LHO doesn't accept the insufficient bid. The offender, playing Acol, has 15-17 points and a club suit. Is 1NT a comparable call?


  • Pretty sure not. It'd fit the hand, but 1C has a wide range of different hand types available, it's not "same or similar" to a 1NT overcall. You might argue the 1NT overcall is a subset of the 1C bid, certainly in acol most 15-17 hands with a club suit would bid 1C. But 1NT might also include some hands with shorter clubs, so I don't think that applies either.

    We should be clear when making these rulings of course, that making a non comparable bid is an option, just one that means partner has to pass.

  • (Note: in this post I'm focusing only on the "subset" part of comparable calls, Law 23A2 – the two other possibilities, "same meaning" and "same purpose", clearly don't apply in this case.)

    The 1C opening denies certain hand types that the 1NT overcall doesn't deny, such as a balanced hand with 5 diamonds. That seems like more than an isolated exception, which is enough to make the 1NT call incomparable.

    There are some 5-card major systems which open all balanced hands outside the 1NT range with 1C – I think that if the offender were playing such a system, rather than Acol, it would be comparable (because now 1C wouldn't have denied any of the hands that are included within the 1NT bid).

    When working out comparable calls, the basic idea is to try to work out if there are any more hands which the offender's partner is able to rule out based on the combined information from the retracted call and the replacement call, that they couldn't rule out based purely on the replacement call (in other words, the offender's partner has "useful UI"). Minor differences can mostly be ignored (e.g. if the retracted call shows 15-17 balanced and the replacement shows 15-18 balanced, now the offender's partner knows that the offender doesn't have an 18 count, but that's such a small part of the range that it's normally better to use the UI rules rather than considering the call incomparable – incidentally, such a call would be comparable under 23A1 in addition to 23A2). But when the difference is more than minor, like it seems to be in this case, it's enough to stop the call being comparable.

  • A meaning attributable to the 1C overcall is that the offender thought he was opening 1C, which just happened to be the case. (The question in the OP was originally posted in another forum. The board itself was played at a club session somewhere in the Home Counties.)

    In the offender’s system, a 1C opening would show 4+ clubs and be around 11-20 HCP.

    A substitution of 1NT would show about 15-17 HCP and normally some reasonably good
    Stoppage in the club suit that has been opened on the right.

    The HCP range of the 1NT overcall is far more precise than the HCP range of a 1C opening for the offender, so in terms of HCP, a 1NT overcall would be a subset of the hands that would open 1C

    What about the general shape? A 1C opening for the offender would show many possible shapes of hand from flat to very unbalanced. A subset of all those hand shapes would be a fairly balanced hand. A 1NT overcall would mostly show a more precise shape, the exception being that there might just possibly be a longer non-club suit than club suit.

    The main problem comes with the length of the club suit. For the offender, a 1C opening would show four or more clubs and a 1NT overcall would tend to have at least three, though probably more often, four clubs, so might have as few as three clubs and, on a fairly rare day only two clubs.

    If we allow 1NT as a Comparable Call, then what would the offender’s partner know? He would know that the offender has got more than two or three clubs.

    The WBF Commentary on the 2017 Laws says of Law 23:

    “The concept of comparable calls is fundamental to the rectification of insufficient bids and calls out of turn. When determining whether a call is comparable, some flexibility towards the offender is in order, especially concerning the strength shown. If there is additional information from the illegal call, but the replacement call is comparable, then this information is authorized to the offender’s partner. If the extra information turns out to provide the offending side with an advantage, the Director adjusts the score considering the likely outcome had the illegal call never occurred.”

    This “flexibility towards the offender” is something that the EBU has also advised on.

    The question is how far one can take this leniency.

    I would argue in favour of adopting this leniency sufficiently to allow 1NT as a Comparable Call, but I would quite accept that this is a close decision, and I wouldn’t criticise anyone taking the opposite view.

    Barrie Partridge - CTD for Bridge Club Live

  • I personally would have accepted the 1NT as a Comparable Call, as it appears to fit Law 23A2. It has to fit only one of 23A1, OR A2, OR A3 to be comparable.
    A replacement bid of 1NT 15-18 pts, implying Clubs / Club-stopper(s) seems reasonable. I can’t think of any other replacement bid which wouldn’t have silenced partner.
    If it’s not correct, then As TD you always have Law 23C. “Non-Offending Side Damaged” to fall back on.
    Kind regards Steve
  • @SteveMap said:
    I can’t think of any other replacement bid which wouldn’t have silenced partner.

    The laws do not guarantee that there is a replacement which does not silence partner.

    Assuming some 5332 hand (with 5 diamonds and a club stop) open the 5-card suit but could overcall 1NT, the 1NT replacement is not a subset of the 1C insufficient bid. 5M332 are also possible 1M opening bids and 1NT overcalls.

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