[jschafer]

---

West leads the ♦K and continues a ♦ to the Queen and Ace. On the third round of diamonds you decide to ruff with the 7, West overruffing with the 8. West now continues with the ♣Q, which you win with the Ace while you and East follow small. Matchpoints, how do you continue?

If you play on ♠:

Spoiler

You find out West started with Q85

[quiddity]

This doesn't seem like a straightforward hand to me.
If we trust the opponent's carding (placing East with the ♣K) and take the 5-9 range seriously then we can place West with the rest of the high cards. We could ruff a club to get the count and then run trumps to get to

-
J94
-
97

opposite

4
AQ75
-
-

If we think East started with 3=2=6=2 (East drops the club king on the second round) then West will now be guarding hearts and clubs and will have to come down to 4 hearts and a club. Now we lead a heart and West follows with a small spot. One possibility is to finesse the 9. The other possibility is to win the J in dummy, ruff a club to remove West's exit, and lead the ♥Q to squash East's Tx or 8x. West can win but will either have to lead the ♥T, making our 7 good, or else let us in dummy to cash the good club. The finesse gains when East has xx (just a single possible holding after West follows to the first round) and the endplay gains when East has Tx (3 possible holdings) so the endplay is better.

However, back to the beginning position. It seems pretty obvious for West to falsecard ♣Q from KQ here (he knows that we're in dummy for the last time to take a potential finesse and he knows we're trying to count East's hand) and the line above could well lose to ♥Kx with East or ♠Qxx with East. So maybe we should finesse after all - but which suit? At this point I don't know how to proceed. Finessing the heart gives us the chance to play for the drop in spades later. but in this case we have good chances to limit our heart losers to 1 without taking the finesse so my intuition is to try the spade hook.

[Quantumcat]

West must have the rest of the high cards.

I will play two high spades. If I don't see the queen then West has it. If I see the queen I'll draw the last trump with the jack.

I will play a low heart towards the jack. If it wins, I'll hope the hearts are 3-3 or that East has a doubleton ten and play Ace then another.

They will take two diamonds, two trumps, and one heart on this plan, OR two diamonds, one trump and two hearts, OR two diamonds, one trump and one heart.

I'll succeed if either:

-Trumps are 3-3
-Hearts are 3-3
-Hearts are 4-2 with doubleton ten
-Hearts are 4-2 with doubleton king with West (unlikely)
-West mistakenly rises with the king of hearts

Probably there is deeper analysis, but that's what I'd do at the table and I'm satisfied with its chances of success.

[jschafer]

quiddity, on 2011-August-20, 18:54, said:

It seems pretty obvious for West to falsecard ♣Q from KQ here

Wouldn't West want to show as many hcps as possible to pursuade declarer to take losing finesses? Surely making it look like East has the K♣ and no other points is counter productive if you want declarer to hook in a major?

[quiddity]

jschafer, on 2011-August-21, 05:28, said:

Wouldn't West want to show as many hcps as possible to pursuade declarer to take losing finesses? Surely making it look like East has the K♣ and no other points is counter productive if you want declarer to hook in a major?

If West has ♣K and East has a major suit honor then West does not want declarer to hook.