Sunday, October 3, 2010

Another Compound

Dlr E
Vul NS
IMPs

♠ A 8 7 3
A Q 10 2
K 7 6 5
♣ 6
♠ K 2
K J 8 7
A J
♣ A K Q 10 4

West
North
East
South
3♣ 3NT
5♣ 6♣ Pass 7NT
All Pass

♣3 led. RHO puts up the Jack. How do you play?

FWIW, RHO is an honest customer, LHO not so much. You can confirm this by playing another club.

My line and further analysis is below.



I tested one more club and LHO pitched ♠4 (I pitched ♠3 from dummy). Then 4 rounds of hearts, LHO following up the line, while RHO pitched ♣7, ♠5, then 4.

There's definitely a squeeze available at this point, but I still haven't committed to which one to play for. ♠K drew the Jack from RHO and 6 from LHO. Now I can afford another club before making up my mind: LHO pitched ♠9 while RHO followed with the 5. This is the ending:


 
♠ A 8
K 7 6
♠ 2
A J
♣ 10 4


RHO is down to a club stopper and 3 pointed cards. If he started with 4 spades (and so still has that suit stopped), LHO made a very tricky pitch from 3=4=5=1 at trick 2 (and again on the last trick). Not to mention that the aggressive 3♣ opening seems much more likely with 4 diamonds than 4 spades. So, I played a spade to the Ace, and when RHO showed out I claimed: he must pitch his diamond guard here, then A, ♣10 squeezes LHO in diamonds and spades.

If I had thought that RHO guarded spades but not diamonds, then K, A, ♣10 would effect a similar squeeze.

Technically this was just a double squeeze (LHO guards spades, RHO guards clubs, both guard diamonds), but if RHO had started 3=1=3=6 it would have been a true compound (a Type-R Unrestricted).

How about the defense?

East is going to need to make 2 pitches on the hearts, and then declarer is going to need to guess which of the pointed suits East still guards. If, as on the actual hand, East pitches one from each suit, he'd better not have started 3=3 or declarer cannot go wrong. On the other hand, even though East has had to make 2 pitches, always pitching one from each reveals nothing about which suit started longer. If West also pitches one from each suit (he has to make 2 pitches on clubs), declarer faces a straight guess (ignoring the auction), even though this is (or at least looks like) an unrestricted compound.

In compensation, if East did start 3=3, he must pitch 2 from a single suit, and declarer will almost always go right by playing that suit to now be unguarded. When East is actually pitching 2 from a 5 card suit (which he should do instead of 1 from each), declarer should normally go wrong (3-3 vs 5-1 is 25:3 a priori, though knowing an opponent's preempting style might be enough to overcome that).

I guess when the layout is such that it's not a true compound, just a double, that the position-tightening does not actually put anyone under pressure and so it makes sense that proper discarding reveals virtually nothing. There's always a double squeeze present, but it's more or less a toss up as to which to play for if both defenders are perfect. In contrast, when it is a true compound, East is squeezed twice and his discards are much more revealing, making it around 80% that declarer gets it right even against perfect defenders.

Obviously in practice a psuedo-squeeze is much more likely than this layout and West should be minimizing the chance of screwing that up.

Some minor technical points:

1. I should not have played a club at trick 2. RHO might not appreciate what is going on and if he pitches 2 clubs I'm spared any guess.

2. If I do play a club, I might as well pitch a heart. LHO might have trouble pitching from a 4 card holding in diamonds or spades. Also, I might as well play a 3rd (but not a 4th!). This gets more information from LHO early, without really helping RHO much if at all.

3. When crossing back to hand, I should probably use A in case the Q has been bared.

Finally, the J was not strictly necessary, but it does help slightly in constraining the defense. Earlier I suggested that LHO pitching a spade early (and another later) from 3=4=5=1 would be tricky. This follows the general "principle" (technically this principle is false, but that's another post) of not waiting to the last possible moment to release a guard if you're squeeze. Since West is going to be squeezed in diamonds and spades later in the hand, if he anticipates this he has a good chance of leading declarer astray by pitching from his shorter suit early. However, thanks to the J, he actually can't get away with pitching 2 diamonds (he started with Qxx). At double dummy the clash menace is irrelevant, but at single dummy it puts additional constraints on the defense and may make reading the position slightly easier.




The BBO record is here.

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Thursday, September 23, 2010

Finesse played as a suicide compound

♠ A 10 3
A 4 2
Q 7 6 2
♣ A 9 8
♠ Q 9 2♠ J 7 5 4
6 5J 10 9 8
A K J 10 58 3
♣ Q 10 2♣ J 5 3
♠ K 8 6
K Q 7 3
9 4
♣ K 7 6 4

West
North
East
South
1 1NT Pass 2♣
Pass 2 Pass 3NT
All Pass

J led. I ran this to my ace and crossed to dummy with another heart to lead a diamond. The Q was allowed to hold, then I exited a diamond. When West ran diamonds, East had to pitch 2 more black cards in this ending:

♠ A 10 3
♣ A 9 8
♠ Q 9 2♠ ? ? ?
10 9
♣ Q 10 2♣ ? ? ?
♠ K 8
Q 7
♣ K 7

East must unguard a black suit. Win West's continuation with a king in dummy, then cross in the suit East doesn't guard and back to dummy's remaining K. One of these tricks will squeeze East again in the other black suit and hearts, then Q will squeeze West in the black suits.

As shown, West could defeat this by exiting without cashing all diamonds. In practice, though, I held ♠J (you did notice the very light 1NT overcall, right?) and could always fall back on that finesse.

The BBO record is here.

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Wednesday, August 18, 2010

Which squeeze?

Matchpoints

♠ 3
Q J 4 3
A Q J 4
♣ K 9 3 2
♠ A K Q 10 6 4
K 5
K 5 2
♣ A 7

You're declaring 3N against a diamond lead from a defender very fond of passive leads. You win, play a heart to the K and Ace, and a club comes back. How do you play for 12 tricks? Let's assume that the defense isn't very deep; the inferences from not ducking HA or not leading a 2nd heart are too complex.

Discussion below...




You might as well run diamonds and come down to:

♠ 3
Q J 4
♣ K 9 3
♠ A K Q 10 6
5
♣ 7

No chances have been eliminated by doing this. From here, I'm pretty sure nothing is given up by cashing hearts, either (since only one player can guard that suit). After that, there's a fork, though:

[All lines work when the spades split or SJ falls, both have some vig for 5-2 clubs and a club-something squeeze]

a) test spades, then hope for a double squeeze around clubs. Requires long heart on left, long spade on right.

b) cash CA, then hope for spades and hearts in the same hand.

[If someone shows out on hearts, play RHO for spade length (likely if he's short in hearts, necessary if he's long) and choose accordingly]

How do you compare majors divided in a specific way vs majors together but in either hand? See Rubens's latest book. Perhaps I'll come back later and work it out in detail, but I'm pretty sure line b comes out slightly ahead.

For example, assume both red suits are 3-3. Then spades, if they don't split, are very likely to be 4-2. That would make it 5:3 that the odd heart is in the other hand, but that only works when it's hearts-left-spades-right-not-vice-versa, which cuts the odds to 2.5:3. But, it gets a bit closer after accounting for 5-1 spades.


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Tuesday, August 17, 2010

Test Your Play Again -- solution

I posted this recently:

Matchpoints, favorable.

♠ 3 2
Q 9 4 3
K
♣ K Q 10 9 3 2
♠ A Q J 6 4
J
A 9 5 2
♣ A 8 7

This is slightly modified from a hand I played on Saturday. LHO opened 1♠, RHO passes, and you wind up in 3N. ♠10 led, RHO shows out, pitching a diamond. When you play a club to the king, everyone follows.

How do you play?

Seems like LHO must have all the major suit honors. So you could try running all your minor suit winners to come down to a 4 card ending, then exit a heart to lose 2 hearts but score 2 spades at the end, for 11 tricks total.

However, even if LHO has both heart honors, the defense might be able to defeat this plan. How do you counter?

Answer below...



The problem is that LHO can pitch a heart winner in order to hold a diamond link to partner, who will have some good diamonds left. So, after ♣K (in case they're 4-0), unblock
K and play a heart. LHO can't cash 2 hearts or your 11th trick is established, but the position becomes a trick tighter. In the 3 card ending LHO must keep 2 spades and the other heart winner, and now it will be safe to throw him in.

In practice, one of my small diamonds was a heart. I played this way and successfully executed the endplay, but I could have almost as well just established a heart trick.

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Sunday, August 15, 2010

Test Your Play Again

Matchpoints, favorable

♠ 3 2
Q 9 4 3
K
♣ K Q 10 9 3 2
♠ A Q J 6 4
J
A 9 5 2
♣ A 8 7

This is slightly modified from a hand I played on Saturday. LHO opened 1♠, RHO passes, and you wind up in 3N. ♠10 led, RHO shows out, pitching a diamond. When you play a club to the king, everyone follows.

How do you play?



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Tuesday, August 3, 2010

Test Your Play -- solution

♠ A J 7 4 3 2
Q
A 10 2
♣ J 4 2
♠ 10
A K 10 6 4 2
K Q 9 5
♣ 10 7

West
North
East
South
1
Pass 1♠ Pass 2
Pass 3♣ Dbl 3
Pass 4 All Pass

Let's say the defense starts 3 rounds of clubs as you ruff (LHO started with Axx; for purposes of this problem you can assume RHO has 5 clubs) and all follow to the Q. Now what?

As discussed yesterday, I crossed back with a low diamond to play 2 more trumps, RHO pitching a club on the 3rd round. That left this ending:

♠ A J 7 4
A 10
♠ 10
10 6
Q 9 5

It seems like you basically have to pick up diamonds, and that playing for 3-3 or Jx is best, but I figured that I didn't have to do that right away. So, I tried A (both follow, no J), ♠A and ruffing a spade. RHO followed with the king and the eight. Seems awfully likely that he has KQ87, so I exited my last trump, pitching the blocking 10 and endplaying LHO.

The main hint is "the blocking 10". Say I had unblocked that card at trick 5, leaving a very slightly different end position:

♠ A J 7 4
A 2
♠ 10
10 6
Q 9 5

Now you have a much better option: ♠A, spade ruff, A, spade ruff.

Case 1: LHO follows to 3 spades, and must be 3=4=3=3, so cash your diamond and concede trick 13.

Case 2: LHO only has 2 spades. Now she has 2 losing options: overruff and lead a diamond into your tenace, or pitch a diamond, allowing you to complete your elopement.

But, I think you can do better still. See below.



Basically, if RHO shows up with heart length, you'll probably regret unblocking 10. So, I think the best line is to not touch diamonds, but cross back to hand with a spade ruff. Now if LHO shows up with heart length, play along similar lines. If RHO shows up with heart length, then if he had a stiff spade play for 3-3 diamonds. If not, play K and hook 10. If RHO started with 2425 with both red jacks, you'll go down.

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Monday, August 2, 2010

Test Your Play

♠ A J 7 4 3 2
Q
A 10 2
♣ J 4 2
♠ 10
A K 10 6 4 2
K Q 9 5
♣ 10 7

West
North
East
South
1
Pass 1♠ Pass 2
Pass 3♣ Dbl 3
Pass 4 All Pass

Let's say the defense starts 3 rounds of clubs as you ruff (LHO started with Axx; for purposes of this problem you can assume RHO has 5 clubs) and all follow to the Q. Now what?

I think there's a great line, including at least one very pretty variant. A sort of hint is below the fold: the inferior line I actually took.




I crossed back with a low diamond to play 2 more trumps, RHO pitching a club on the 3rd round. That left this ending:

♠ A J 7 4
A 10
♠ 10
10 6
Q 9 5

It seems like you basically have to pick up diamonds, and that playing for 3-3 or Jx is best, but I figured that I didn't have to do that right away. So, I tried A (both follow, no J), ♠A and ruffing a spade. RHO followed with the king and the eight. Seems awfully likely that he has KQ87, so I exited my last trump, pitching the blocking 10 and endplaying LHO.

More on Tuesday.

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