[Wackojack]

{comments}

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Yesterday I looked ar Richards commentary on youtube. On this hand the rest of the field played on clubs and finding them 3-3 with the Queen well placed made 11 tricks. Richard and I as declarers played on diamonds and made 10 tricks for an equal bottom. He did comment that he wasnt sure that he played against the odds. That led me to giving it some thought. I put the suits into the odds tables: http://www.automaton.../en/OddsTbl.htm and came up with this analysis.

Play on clubs (no losers 17.8%) Result 11 tricks
Play on diamonds (1 loser 12.4%) Result 11 tricks.
Thus the upside on playing clubs rather than diamonds = 5.6%.

Play on clubs ( 1 loser 43.6%) Result 10 tricks
Play on diamonds (2 losers 78%) Result 10 tricks.

Play on clubs (2 or more losers 38.6%) Result 9 tricks or fewer
Play on diamonds (3 or more losers 9.6%) Result 9 tricks or fewer.
Thus the downside on playing clubs rather than diamonds = 29%.

This suggests that the play on diamonds gives give you the better match point odds.

The lead of a heart rather than a spade may affect the odds slightly. I got a heart lead and I think I incorrectly let it run to my Jack rather than take with the Queen in dummy. Nevertheless that did not affect the result.

Am I right?

[hrothgar]

Thanks for posting this hand. I had meant to do so, however, work is a bit insane this week.

[Cyberyeti]

Well you could have brought the diamonds in, is the way you played on them correct ?

[hrothgar]

Cyberyeti, on 2016-March-10, 07:20, said:

Well you could have brought the diamonds in, is the way you played on them correct ?

We both brought the Diamonds in, but the 3-3 club break with the queen in the slot gave the folks who played on clubs an extra trick...

[Cyberyeti]

hrothgar, on 2016-March-10, 07:25, said:

We both brought the Diamonds in, but the 3-3 club break with the queen in the slot gave the folks who played on clubs an extra trick...

You can bring them in for one loser, which gives you 11 tricks.

Alternatively you can have a shot at the diamonds and revert back to the club finesse if you fail, but either way running 7♦ from hand seems a decent start.

[manudude03]

I watched Richard's video too. On a spade lead, you might not be able to afford losing 2 diamonds (opps lead spades every time and now they have 2 tricks with 2 spades ready to cash and still have the ♥A). If you play on clubs, even if the finesse loses, you will be able to switch to hearts after testing clubs and always make at least 9 tricks.

On a heart lead, if you play on diamonds first (going by cyberyeti's line), East wins and plays a heart (ducked), now you will have some unpleasant choices about how to continue (best probably to cash the ace of diamonds and take the club finesse which would lead to 11 tricks), while playing on clubs initially all but secures the contract.

[hrothgar]

Cyberyeti, on 2016-March-10, 07:20, said:

Well you could have brought the diamonds in, is the way you played on them correct ?

Guess that brings up another interesting question.

What is the best way to play this suit?

[Cyberyeti]

hrothgar, on 2016-March-10, 08:35, said:

Guess that brings up another interesting question.

What is the best way to play this suit?

both in abstract and in the context of the hand, imagine that the second heart is ducked and the opps have 2 more to cash, so you're only making 9 if you lose 2 diamonds. Also if the hand with 5 hearts has ♦Hxx you're going off.

A♦ plays diamonds for 1 loser if E has K, Q, 10xx, and for 2 losers on any 3-2 bar 10xx and x or 10 (but note that it looks like some of the 2 loser cases allow the wrong hand in so the hearts will cash)

Running 7♦ is more complicated to calculate, depending on what you think W will play from H10 and 10x, and this governs what you should do on the second round.

[WesleyC]

At MPs you're definitely better to play on clubs, at IMPs it's pretty close between the 2 lines.

The error in your maths logic is that playing diamonds for 2 losers doesn't automatically lead to 10 tricks.

If hearts break 4/3 (and the 4th heart is either with the ♥A or with the 2nd diamond winner) then you will only win 9 tricks.
If hearts break 5/2, then you might win 10 tricks, or maybe 8 (if the 2nd diamond winner is with the long hearts).

Although your analysis of playing on clubs is correct, it ignores the 14.8% chance that you find out clubs aren't working after 2 rounds and get to choose a different plan. If clubs do turn out to be 5-1 (which is a majority of these 'replan' cases) you might be able to scramble home in diamonds with the defence unable to cash our their tricks.

[ye17]

WesleyC, on 2016-March-10, 10:30, said:

At MPs you're definitely better to play on clubs, at IMPs it's pretty close between the 2 lines.

The error in your maths logic is that playing diamonds for 2 losers doesn't automatically lead to 10 tricks.

If hearts break 4/3 (and the 4th heart is either with the ♥A or with the 2nd diamond winner) then you will only win 9 tricks.
If hearts break 5/2, then you might win 10 tricks, or maybe 8 (if the 2nd diamond winner is with the long hearts).

Although your analysis of playing on clubs is correct, it ignores the 14.8% chance that you find out clubs aren't working after 2 rounds and get to choose a different plan. If clubs do turn out to be 5-1 (which is a majority of these 'replan' cases) you might be able to scramble home in diamonds with the defence unable to cash our their tricks.

That is roughly the view I took. I would prefer to find out if the clubs are working first.
I was allowed to make 12 tricks when W ducked the second heart

[Wackojack]

WesleyC, on 2016-March-10, 10:30, said:

Although your analysis of playing on clubs is correct, it ignores the 14.8% chance that you find out clubs aren't working after 2 rounds and get to choose a different plan. If clubs do turn out to be 5-1 (which is a majority of these 'replan' cases) you might be able to scramble home in diamonds with the defence unable to cash our their tricks.

If clubs turn out to be 5-1 (West having 5) and you go to plan B (diamonds) then you will almost always be 1 trick behind those who started on diamonds. So in MP this has to be inferior.

WesleyC, on 2016-March-10, 10:30, said:

The error in your maths logic is that playing diamonds for 2 losers doesn't automatically lead to 10 tricks.

If hearts break 4/3 (and the 4th heart is either with the ♥A or with the 2nd diamond winner) then you will only win 9 tricks.
If hearts break 5/2, then you might win 10 tricks, or maybe 8 (if the 2nd diamond winner is with the long hearts).

Yes I did recognise that this affected the odds. As I see it, it will further depress the upside on playing diamonds first, but I am not sure that it affects significantly the far bigger downside on playing clubs first.

My conclusion now is that it is very close, so that playing on diamonds first is not obviously inferior.

[Wackojack]

Cyberyeti, on 2016-March-10, 07:49, said:

You can bring them in for one loser, which gives you 11 tricks.

Alternatively you can have a shot at the diamonds and revert back to the club finesse if you fail, but either way running 7♦ from hand seems a decent start.

Yes. My table says that the odds of keeping to the loss of 1 trick only by intrafinessing the 7 (and then finessing on the way back) is 13%. Almost identical odds to playing ace and another so your choice would be according to who you thought had the ace of hearts. In other words if as is likely you are going to lose 2 diamond tricks, then you want to lose first to the hand you think has the ace of hearts.

[WesleyC]

Wackojack, on 2016-March-10, 13:25, said:

My conclusion now is that it is very close, so that playing on diamonds first is not obviously inferior.

If you choose to start your post with maths, why make your conclusion without any mathematical justification?