[Phil]

Saw this one yesterday:

J3

A87642

[ahydra]

Run the J to pin a singleton 10 or 9? Don't see much else - we don't have any useful cards at all (except the Ace lol), so just have to hope they split nicely.

ahydra

[Cyberyeti]

 ahydra, on 2012-August-10, 10:06, said:

Run the J to pin a singleton 10? Don't see much else - we don't have any useful cards at all (except the Ace lol), so just have to hope they split nicely.

ahydra

Has the added advantage that Q109x might just cover.

[ahydra]

 Cyberyeti, on 2012-August-10, 10:17, said:

Has the added advantage that Q109x might just cover.

hehe... soon to be followed by the wailing, screaming and gnashing of teeth of opponents fighting over whether playing the Q is correct or not, no doubt.

ahydra

[Phil]

 Cyberyeti, on 2012-August-10, 10:17, said:

Has the added advantage that Q109x might just cover.

I think East covers with any four card holding.

Not much to this, but keep it in your memory banks.

[JLOGIC]

For 5 tricks with Jx in dummy, low to the jack, hope they pop with QT or KT on your left, then lead the jack and hope they don't cover with H9 on your right which they won't since they'll assume you have ATxxxx and that their only hope is for you to play for KQ doubleton on your left.

lol

[benlessard]

Good one Justin ! Tough combo for defense.

If we know that south is ATxxxx,

Quickly I think west should never go up with HT but when hes got Hx hes got to play high around 25% to protect the potential KQ (assuming that all players know declarer need 5 tricks from the suit.

when west is in the dark, he must sometimes but rarely play high from Hx to protect his KQ out of is Hx pool of hands. However with HT i think he should never go up high.

[lalldonn]

 benlessard, on 2012-August-10, 14:57, said:

Good one Justin ! Tough combo for defense.

If we know that south is ATxxxx,

Quickly I think west should never go up with HT but when hes got Hx hes got to play high around 25% to protect the potential KQ (assuming that all players know declarer need 5 tricks from the suit.

when west is in the dark, he must sometimes but rarely play high from Hx to protect his KQ out of is Hx pool of hands. However with HT i think he should never go up high.

Why should west just lose his trick if south has AKxxxx or AQxxxx? Maybe you wouldn't always play those suit combinations by leading low to the jack, but some people would especially if the hand has other considerations.

[JLOGIC]

 benlessard, on 2012-August-10, 14:57, said:

Good one Justin ! Tough combo for defense.

If we know that south is ATxxxx,

Quickly I think west should never go up with HT but when hes got Hx hes got to play high around 25% to protect the potential KQ (assuming that all players know declarer need 5 tricks from the suit.

when west is in the dark, he must sometimes but rarely play high from Hx to protect his KQ out of is Hx pool of hands. However with HT i think he should never go up high.

If declarer has A9xxxx and needs 5 tricks and that is all there is to the hand, there is nothing you can do with HT since declarers only play in the suit for 5 tricks. I suppose your point is that you can protect against this A8xxxxx opp Jx coup by going up with the honor, it is pretty artificial but yes if you know declarer has Axxxxx then I suppose you're right.

In the real world you might be embarrassed if you play the T from QT and declarer has K9xxxx when he was supposed to have the ace though Or if he has AQ9xxx when you have KT and he wasn't supposed to have the Q. Etc etc.

It's worth noting that the ten would be a good play if declarer only needed 4 tricks and had A9xxxx though since he would then safety play against your stiff ten.

Going up with the honor is also good for entry purposes (you force declarer to cross to dummy to lead the jack, and then cross back to his hand to cash the ace, possibly a 2 entry swing compared to the ten).

Anyways, the possibility of declare having A8xxxx and faking ATxxxx against my partner is not really high on my list of concerns, I have never seen this happen and was just being silly but it's a good point.

[benlessard]

I was trying to solve the simpler core problem first (Jx--Atxxxx) before the "others variations". Its purely a theoric pov and has very little IRL application.

If

Jx

ATxxxx and all side know that declarer need 5 tricks and defense know the declarer cards.

low to jack hoping to win against pick up Hx the relevant cases are

Hx--Hxx = 20%
KQ--xxx = 3%
xx--KQx = 10%

If west never play 2nd hand high declarer is going to win 23%.
If west always play high declarer success = 30%
My guess is if West mix his play in the proper proportion he can hold declarer only to the average of 20% & 23% = 21.5%. My guess for west mix is 1/8 he must go high with Hx, i tought it was 25% but there is a restricted choice type of split (one case of KQ for 2 case of Hx, Kx&Qx)

-------------------------
Cases of HT

If declarer got
Jx

A97xxx

is only legitimate play is against HT--Hxx so it doesnt matter going up or not hes going to succeed 6%.

if hes

Jx

A987xx

going up with HT or playing low from Tx will always fail.

But you have to hedge them together because playing the T from Tx might give the contract when declarer doesnt have the 8. This also mean declarer you should play 7 to the J and not low the the J.

-----------------------------
against
Jx

K9xxxx

an in the dark west will look foolish playing low from QT. But IMO it must still be done a tiny amount of times, because you need to hedge against partner possible KQx. Of course anytime you think declarer has like 3% of having the K and not the A, dont play low with QT. But agaisnt some players ill noticed their disgust and know if they wont hold the A.
--------------------------
The only conclusion I can get is when your in the west seat and dont know declarer hand and dont know how many tricks he need or if your in MP your in a tough seat.