I have heard that at some point in the past, a common defence against a strong 1 club opener is:

1S: I have 13 cards.

What's the reason this defence has fallen out of favour? Could it be that it's mechanically unsound (eg. too vulnerable to penalty doubles). Or could it be that the defence is perfectly fine, but simply is outlawed as a "purely-destructive overcall"?

If the later, why are purely-destructive overcalls outlawed? Isn't interference part of the game, especially over greedy bids such as Strong 1C that attempt to preserve a lot of bidding space?

2 Answers 2


This treatment is illegal in the ACBL. It falls under the definition of a "Purely Destructive Initial Action":

"Purely Destructive Initial Action”: An opening bid or an overcall that satisfies
none of the following:
a. 4+ cards in a known suit.
b. 5+ cards in one of two possible suits.
c. 5+-4+ distribution in any two suits.
d. An either/or combination of any two of a, b, or c (which may be the same option
e. A Three-suited hand.
f. At least Average strength.
g. Any Natural or Quasi-Natural opening bid.

According to the ACBL convention charts, purely destructive opening bids and overcalls are forbidden at all levels.

There are a number of reasons people give that purely destructive actions are forbidden. Those in favor of the prohibitions argue that they reduce the skill aspect of the game, making it more random, or that totally unrestricted bidding rules make it impossible for pairs to prepare adequately for all possible agreements and therefore give an undesired advantage to pairs that employ agreements that are novel for the sake of being novel rather than good. Those opposed to the prohibitions argue that these rules are meant to coddle the masses who pay the vast majority of card fees and dues to the ACBL.

  • How about under non-ACBL rules? Is this treatment allowed there? If so, is this treatment (or a treatment that includes other bids for certain hands, but defaults to 1 Spade) even +EV to use, compared to alternative defences against strong 1 club?
    – Han Guo
    Commented Nov 30, 2023 at 18:00
  • 2
    I'm not really familiar with bidding regulations in other jurisdictions. I'd guess that this is probably -EV. Most strong club pairs can easily deal with 1-level interference, and your partner won't be able to use information about your hand to bid higher.
    – ruds
    Commented Nov 30, 2023 at 18:03
  • Level 4 EBU rules permit any defence to artificial or forcing opening 1 bids in second seat: "Any partnership understandings are permitted after (a) an artificial or forcing one-level suit opening. Level 4 is the level most commonly defined for club or tournament play in England. mjbridge.info/opener/page7.html As a former Precision player, I was very surprised to learn this. I would have assumed that random 1S overcalls were not permitted. (b) an opening bid of 1NT or above."
    – AlDante
    Commented Jan 26 at 21:47
  • Note that something close to "13 cards" is legal: "willing to play at the 2 level". All you need is a 5 card suit. Not "purely destructive", because d: b. once for "5+ in a major", b. again for "5+ in a minor". And as long as it's not required - so not 1-spade "promises" a balanced hand - or you play something strange like "double is reds or blacks, 1H is majors or minors, 1S is 5+ in any suit, 1NT is two non-touching suits ('roundeds and pointeds')" if you want to play "we never pass", fine.
    – Mycroft
    Commented Apr 5 at 22:51

Such a convention may be legal in some parts of the world (Europe is more permissive than ACBL). But, I have never heard it played here in Finland (and we are quite permissive with conventions unless playing in an event intended to onboard newbies). I don't have the mileage to say for sure, but my guess is that most players are too partnership oriented to try something like this.

My repertory vs strong clubbers consists of the usual overcalls, the pre-empts, and then selected 2-suited poisons. The point is that a random 1S won't do much against expert opponents. The gains from interference come when you can really jam their auction. To do that you need to find your own fits — you want partner to raise somewhat safely. I guess you could squeeze one such bid into a defensive system, but as (necessarily) it will be a low level call, it won't do much damage alone. I want to increase the chances of partner to continue the interference instead.

Compare the sequences:

  • (1C strong)-1S (random)- D (strength, but no 5 card suit)-? What can partner do safely here? Nothing much. Have the opponents been disturbed? Not much, they can start searching for their fits at the two level, and their combined strength makes it safe.
  • (1C strong)-2H (hearts and a minor)- D (strength, either exactly 4 spades or more strength)- 4H! What can the opening side do here? The strong clubber needs to take a view on slam hunt right away. 4S is an option, but doesn't really invite partner to continue. When their extra strength is split between the two hands, the opps have a difficult decision.

Even a more modest interference like 1C (=strong)-1D (=natural)-D (=GF strength, 4+3+ in majors or some other meaning), 3D inconveniences the opps. Is 3NT still ok? How to agree on a suit in a forcing manner? True, they now have Double and the cuebid of 4D in their arsenal, but they have been robbed quite a bit of the space to investigate.

So the downside of a random overcall like this is that partner is left equally in the dark. This may be why partnership oriented players dislike it.

There is also the following rule/ethics issue. Unless you bid 1S over an opposing strong 1C every time when you cannot take some other, systemically described action, your partner will gradually learn about your motives and tendencies. When such partnership history builds up, the meaning of the 1S bid will no longer be random, and needs to be disclosed to the opponents (even if undiscussed). This is a grey area, and gives the TD a headache. I'm no bridge lawyer, but I would say, by common sense more than anything else, that an established partnership cannot credibly claim to have "no agreement".

  • Actually, given that an established partnership might only see a strong club opened against them 5 times a year even playing regularly in tournaments, a 'no agreement' claim is not so hard to believe. (I think I'm the only person regularly playing strong club within 200 miles, and that is with a partner farther than 200 miles away.) Commented Dec 11, 2023 at 23:37
  • I believe you @AlexanderWoo. But my experience is very different. 15 years ago may be 20 per cent of the pairs I would meet at the local club played some kind of a strong club. That figure has come down a bit since. But in a matchpoint tournament (geographically wider participation) I still expect to meet several pairs playing strong club, Polish club or a system requiring similar defences. Commented Dec 12, 2023 at 4:20
  • FWIW with my nearly exclusive partner we play a "natural" 5542-system, transfer Walsh -style. 5542 is quite common in these parts, but we do tag on a lot of extras (my partner in particular enjoys tinkering with the system). Commented Dec 12, 2023 at 4:26
  • In the US/Canada, it's not uncommon to have a tournament where all 30 pairs are playing more or less sophisticated versions of Std Amer or 2/1. Maybe you'll get a pair or two playing a different notrump range. Commented Dec 12, 2023 at 4:47

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