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Diamond Dilemma

#1 User is offline   lamford 

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Posted 2018-May-13, 13:47

xxxx opposite K987 for two losers? No oppo bidding and plenty of entries.
I prefer to give the lawmakers credit for stating things for a reason - barmar
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#2 User is offline   apollo1201 

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Posted 2018-May-14, 13:26

I am pretty bad at that but 4-1 (except stiff honor after K and you put up K on 1st trick) and 5-0 are lost. Only 3-2 splits can give you hope.
If the A is 2nd after your K, you need to duck twice. If 3rd after, you’ve lost unless you manage opps to clash their honors. Unlikely even with weak players.
If the A is before your K, you lose 2 tricks if you guess well on playing K.
So it is probably better to play small from both hands (I guess AHHx H is less likely than HHx Ax). Then you play towards K98, and guess if it starts small, honor. If you could gather some info in between (vacant places, HCPs...) you might have some help.
But I’m sure a better player will find it is the other way round 🤣
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#3 User is offline   ahydra 

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Posted 2018-May-14, 16:01

View Postapollo1201, on 2018-May-14, 13:26, said:

So it is probably better to play small from both hands (I guess AHHx H is less likely than HHx Ax). Then you play towards K98, and guess if it starts small, honor. If you could gather some info in between (vacant places, HCPs...) you might have some help.
But I’m sure a better player will find it is the other way round 🤣


That's the line that http://bridge.esmarkkappel.dk/ gives. I couldn't quite make sense of what it's trying to say when you start with small to the 9 vs leading the 9 first - they have the same odds but completely different win/lose layouts.

ahydra
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#4 User is offline   Tramticket 

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Posted 2018-May-15, 06:07

This holding is deceptively difficult to analyse.

Your best chance of making the K is to play towards the king and hope that the A is under the K (50:50). If the A is over the K, you need the suit to be short and duck, but the chances that the A is in a short suit are worse than 50:50. Conclusion: we should be leading towards the K.

We need a second trick with 987. This will be easy if the suit is 3-2 and impossible if the suit is 5-0 either way, so let's consider what happens if the suit is 4-1 either way. Since the opponents hold AQJT between them, we can't make a fourth trick unless two of these clash. This wouldn't happen double-dummy ... but the opponents don't know their combined assets and if (for example) you are sitting with QJTX, wouldn't you split your honours? I am not sure from the opening post whether the XXXX is in dummy and the K987 is in the closed hand? Or the other way round? There are plenty of holdings where the defence might go wrong - which card would you play as a defender if declarer leads a card from XXXX in dummy and you hold AQJX? Playing the X works best but is unlikely I feel.

It's all a bit murky but I think I play low towards the K and duck the first round, then repeat, rising with the king on the second round.
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#5 User is offline   Cyberyeti 

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Posted 2018-May-15, 06:48

View PostTramticket, on 2018-May-15, 06:07, said:

This holding is deceptively difficult to analyse.

Your best chance of making the K is to play towards the king and hope that the A is under the K (50:50). If the A is over the K, you need the suit to be short and duck, but the chances that the A is in a short suit are worse than 50:50. Conclusion: we should be leading towards the K.

We need a second trick with 987. This will be easy if the suit is 3-2 and impossible if the suit is 5-0 either way, so let's consider what happens if the suit is 4-1 either way. Since the opponents hold AQJT between them, we can't make a fourth trick unless two of these clash. This wouldn't happen double-dummy ... but the opponents don't know their combined assets and if (for example) you are sitting with QJTX, wouldn't you split your honours? I am not sure from the opening post whether the XXXX is in dummy and the K987 is in the closed hand? Or the other way round? There are plenty of holdings where the defence might go wrong - which card would you play as a defender if declarer leads a card from XXXX in dummy and you hold AQJX? Playing the X works best but is unlikely I feel.

It's all a bit murky but I think I play low towards the K and duck the first round, then repeat, rising with the king on the second round.


It's even more complicated than that, there are lots of restricted choice implications of which card the first trick is won by, and whether it's auto to play the right card in defence at that point.
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#6 User is offline   Tramticket 

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Posted 2018-May-15, 07:28

View PostCyberyeti, on 2018-May-15, 06:48, said:

It's even more complicated than that, there are lots of restricted choice implications of which card the first trick is won by, and whether it's auto to play the right card in defence at that point.


Agreed! These will tend to apply when you have ducked the first round and play a second round toward K987 and have to decide whether to duck again (playing for ace-doubleton on your left) or rise with the king (playing for doubleton without the ace on your left).
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#7 User is offline   apollo1201 

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Posted 2018-May-15, 10:37

View Postahydra, on 2018-May-14, 16:01, said:

That's the line that http://bridge.esmarkkappel.dk/ gives..

Great link Ahydra!

And kinda proud to have discovered the theoretical play😎
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#8 User is offline   Stephen Tu 

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Posted 2018-May-15, 11:01

The intuitive line for me is simply to play for ace onside doubleton or third. You can save yourself a trick (but still lose 3) by not losing your K to stiff ace offside by leading low to the 7 first if RHO doesn't put in an honor.

Suitplay confirms this is the best line for 2 tricks.

There is an alternate line for 2 tricks, which basically caters to picking up AQ, AT, and AJ doubleton offside. Duck the first lead towards hand regardless, and the second round only go up if RHO has played two of (QJT). So you pick up QTx/QJx/JTx onside, 3 combos, vs line A, but loses an extra trick vs. QJ/QT/JT offside, cancelling out.

But this line needlessly loses all the tricks if RHO has stiff Q/J/T, so it would be weird to play this way without some indications from the bidding.

I suppose if this is not the trump suit, and RHO might mistakenly split from QJTx, you might duck first round completely paying off not getting any tricks to the stiff honor onside to getting 2 tricks from this combo, if 2 tricks needed and IMPS. Then you can do either strategy A or B equally on the 2nd round.
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