[malbaby]

West opens 1C...north overcalls 1D...east bids 1NT...south passes...west passes...north bids 2S...passed out.
North's actual shape is 4S,1H, 3 little diamonds, 5 clubs, and has 12HCP.
E/W assume north has 5D and 4S, with 4 cards in H and C, has "reversed" showing substantial HCP, pass the hand out and defend accordingly.
Director was called during play as it became apparent that N only had 3D.
Club director ruled that because S had passed on 2 occasions and therefore was not influenced by N bidding, N had bid legitimately, and no disclosure was necessary.
Whether the contract makes or not, does north have a duty of disclosure of his D holding, before play commences?

[blackshoe]

No.

[steve2005]

Unless your behind screens or on BBO it would be south who alerts or answer questions.
South I assume has no clue North has 3♦ so has nothing to alert.

If there was a duty for North to explain which in this case there isn't North would explain at end of hand so as not to give info to South.

correction N declarer I thought defender

[sfi]

steve2005, on 2017-November-26, 18:30, said:

If there was a duty for North to explain which in this case there isn't North would explain at end of hand so as not to give info to South.

North is declarer here, so any correction of explanations should be given before the opening lead. However, East-West have not received a mistaken explanation of the agreements, and if North deviates from the agreements it is his/her own business. No duty of disclosure here.

[helene_t]

That South passed on two occasions is not evidence that he didn't use the information that North could have fewer than five diamonds. South might have three spades and four diamonds in which case he needs to explain why he didn't correct to 3♦ - he is of course entitled to bid what he likes but his final pass could be evidence that he has an undisclosed understanding with his partner.

Even if South did not use the information, the opponents are still entitled to it. So if South knew (from agreement or from partnership experience) that North could have fewer than four diamonds he should alert the 1♦ call. And if he didn't, North should explain before the opening lead that he might not have diamond length. He should not say that he actually did not have diamond length (unless his bidding specifically denies diamond length). He only discloses their agreement, not what he has in his hand.

But almost certainly, this was just a beginner's error or maybe North missorted his hand or pulled the wrong card from the bidding box by mistake. In that case, there is nothing to disclose.

So the director probably reached the right conclusion, but for the wrong reason.

[steve2005]

sfi, on 2017-November-26, 18:43, said:

North is declarer here, so any correction of explanations should be given before the opening lead. However, East-West have not received a mistaken explanation of the agreements, and if North deviates from the agreements it is his/her own business. No duty of disclosure here.

Ah sorry without hand diagram I didn't realize that. your right he would have to disclose if there was something.

[steve2005]

helene_t, on 2017-November-26, 18:52, said:

Even if South did not use the information, the opponents are still entitled to it. So if South knew (from agreement or from partnership experience) that North could have fewer than four diamonds he should alert the 1♦ call. And if he didn't, North should explain before the opening lead that he might not have diamond length.

It's pretty unlikely they have an agreement that 1♦ could be made on 3 cards.
More likely he took a flyer or didn't know what he was doing.
If you take a flyer or made a mistake you don't have to tell opponents you may have 3♦ as there is no agreement

[nige1]

malbaby, on 2017-November-26, 17:32, said:

West opens 1C...north overcalls 1D...east bids 1NT...south passes...west passes...north bids 2S...passed out. North's actual shape is 4S,1H, 3 little diamonds, 5 clubs, and has 12HCP. E/W assume north has 5D and 4S, with 4 cards in H and C, has "reversed" showing substantial HCP, pass the hand out and defend accordingly. Director was called during play as it became apparent that N only had 3D.
Club director ruled that because S had passed on 2 occasions and therefore was not influenced by N bidding, N had bid legitimately, and no disclosure was necessary. Whether the contract makes or not, does north have a duty of disclosure of his D holding, before play commences?

It does not matter whether South passed or not. It just depends on N-S methods.

• If N-S have an explicit or implicit understanding to overcall on a 3-card suit and rebid a 5-card suit, then (in most jurisdictions) South should alert 1♦ and, if South does not alert, then, at the end of the auction, North must call the director and tell him what has happened.
• If North psyched (i.e. his bidding is as much a surprise to his partner as to opponents), then no problem.

[malbaby]

OK folks...thanks for the explanations.