[jallerton]

That still doesn't follow. Using that logic one could equally argue that declarer might as well play the queen.

Instead declarer should consider:

A On what layouts would ducking gain over playing the queen?
B On what layouts would playing the queen gain over ducking?
C What is the relative likelihood of A and B?

You mentioned in an earlier post that there is a 'point-a-board' element to the scoring. Although this is relatively minor compared with the potential VP swing for making versus going off in a slam, it would suggest that if close it's better to play the queen to maximise the chance of an overtrick.

[gnasher]

If West plays ♦J:

If you're planning to ruff one diamond and then play a squeeze, the queen gains when West has ♦KJx or ♦J9x, and never loses. (This assumes that East has both heart honours.)

If you're planning to ruff two diamonds, the queen gains when trumps are 4-1 and West has ♦KJx, ♦KJxx or ♦J9x. It loses when trumps are 4-1 and West has♦J9xx.

[lamford]

jallerton, on 2013-October-30, 17:10, said:

A On what layouts would ducking gain over playing the queen?
B On what layouts would playing the queen gain over ducking?
C What is the relative likelihood of A and B?

A Ducking gains when East has ♦Kx or ♦Kxx, and four or more clubs, and West has the other heart honour.
B Playing the queen gains when West has ♦KJxx(x), and has the other heart honour and fewer than three clubs.
C I think A is more likely. After the double of 1H, East is more likely to have each heart honour, but there is a restricted-choice element as well, but these reduce both A and B about equally. I think that at this table it is close, but A is favourite. At another table where they just doubled a 5H response to RKCB, I think that A might be 2-1 on. If we ignore the auction, I think A is a bigger favourite, as not many would find the jack from KJxx. Yes, the ovetrick is unlikely if we play low, that I grant you, but it also makes it less likely that the player has found the J from KJxx(x). If the jack of clubs drops, both lines work.

[lamford]

gnasher, on 2013-October-31, 02:30, said:

If West plays ♦J:

If you're planning to ruff one diamond and then play a squeeze, the queen gains when West has ♦KJx or ♦J9x, and never loses. (This assumes that East has both heart honours.)

If you're planning to ruff two diamonds, the queen gains when trumps are 4-1 and West has ♦KJx, ♦KJxx or ♦J9x. It loses when trumps are 4-1 and West has♦J9xx.

I upvoted your post, but have now reconsidered. If West has KJx of diamonds, there is no gain (except the overtrick) from playing the queen as the king is coming down anyway. And you do not have the 8 of diamonds, so J9x is not good enough. In this line you are down if the red menaces are together and the other hand has ♣Jxxx. You do gain on J98 tripleton with West and the other heart honour with East with clubs not coming in, as you have the seven.

[gnasher]

lamford, on 2013-October-31, 10:13, said:

I upvoted your post, but have now reconsidered.

Probably one of the most ill-judged upvotes I've ever seen.

[jallerton]

lamford, on 2013-October-31, 10:00, said:

A Ducking gains when East has ♦Kx or ♦Kxx, and four or more clubs, and West has the other heart honour.
B Playing the queen gains when West has ♦KJxx(x), and has the other heart honour and fewer than three clubs.
C I think A is more likely. After the double of 1H, East is more likely to have each heart honour, but there is a restricted-choice element as well, but these reduce both A and B about equally. I think that at this table it is close, but A is favourite. At another table where they just doubled a 5H response to RKCB, I think that A might be 2-1 on. If we ignore the auction, I think A is a bigger favourite, as not many would find the jack from KJxx. Yes, the ovetrick is unlikely if we play low, that I grant you, but it also makes it less likely that the player has found the J from KJxx(x). If the jack of clubs drops, both lines work.

At the table where East just doubled the 5♥ response to RKCB, I think the chance of A is close to zero. West would not make a lead-directing double of 5♥ hold ♦K and only the queen in hearts.

[FrancesHinden]

lamford, on 2013-October-30, 09:17, said:

I think that the Lederer should have a cross-IMP table, but organisers have not bothered as far as I can recall.

I don't.
It's an event for teams with hybrid scoring, not for pairs with imp scoring. Why not matchpoint it while you are at it?

[lamford]

FrancesHinden, on 2013-October-31, 16:02, said:

I don't.
It's an event for teams with hybrid scoring, not for pairs with imp scoring. Why not matchpoint it while you are at it?

I thought one would both cross-IMP against the datum and then point-a-board with each of the other pairs in the opposite direction and convert the overall result to VPs. I now think it is not worthwhile as there is no program to do this. If I were NPC of a team of six, of whom four played, I would do it manually for my team only as we went along. Match-pointing the event is indeed meaningless, and I presume your question was rhetorical.

[lamford]

jallerton, on 2013-October-31, 14:42, said:

At the table where East just doubled the 5♥ response to RKCB, I think the chance of A is close to zero. West would not make a lead-directing double of 5♥ hold ♦K and only the queen in hearts.

Then the chance of B is close to zero as well, as you need one heart honour with West to gain, other than the possible point-a-board. And an expert East with both heart honours might well play the king on the first round, the card he is "known" to hold. Also doubling with ♥Qxxx(x) could be right on some auctions, when it gets partner to lead a heart from ♥Kxx(x), or ♥KTx(x) on a different layout. An initial diamond or a club would not have troubled declarer much on this hand! The player who doubled is not on your side, so he could try to muddy the waters by a fairly random double. And I think the chance of someone playing the jack from ♦KJxx(x) is closer to zero. Finally, my 2-1 on was the relative chance of A over B, not an absolute chance. What one is comparing is just the chance of Kx or Kxx with East with that of KJxx(x) with West, and West playing the jack.

The other (unrelated) point against playing the "two ruffs" line is that they could have led trumps to stop this. Of course they do not know the layout when making an opening lead, but they are less likely to lead a trump when they are 4-1.