Early K-J guess

[sathyab]

[hv=pc=n&s=skjhqjt53dt7cat42&n=s765ha987da83ck65&d=e&v=e&b=6&a=1d1h1s2dd2h3d3hppp]266|200[/hv]

 

It's IMP pairs. ♦4 led.

 

1♠ promised a five-bagger. When you ask about the Double of 2♦ after the bidding is complete, East says he meant it as Support Double while West says he took it as just ♦s.

 

If you play a low ♦, East plays the Jack and returns the ♠2.

 

You may not agree with South's 2♥ over the double of 2♦, but that's how the bidding went att.

 

Correction: West did not double 1h, he bid 1s promising a five bagger.

 

 

[auction corrected to reflect the author's intent. -- inquiry]

[Bbradley62]

Coin toss. I might actually take one out of my pocket for this purpose.

[dellache]

Edited in RED : the following is a syllogism. Read future post to see why.

--- Begin Syllogism

I think that playing the Jack is by far the best play : we can afford to go wrong only if we can pick up the Hearts without loss.

 

If we play the ♠King and we are wrong, our chances to find the ♥K by West is almost nil when East opened (and stiff ♥K by East is not very often).

If we play the ♠Jack and we are wrong, our chances to find the ♥K by West is still very reasonable.

 

Hence we play the ♠Jack and maximize.

 

[if we were in 4♥, the best play becomes the ♠K using the same kind of reasoning].

--- End Syllogism

[JLOGIC]

Yes it is a good and common theme that you take a 2 way guess one way because if you are wrong it increases your chance of a side one way hook of being on. If LHO has the SA then RHO will very likely have the HK so playing the king sucks. This is similar to not duplicating rolls in backgammon.

[cherdano]

Obviously I agree with the principle, but nevertheless I don't think it tells us to play the J here.

We have to compare what is more likely:

A) West ♠Q/East ♠A ♥K or

B) West ♠A/East ♠Q ♥K

Since I believe the trick one evidence that LHO has the ♦Q, in case A) there seem to a little more high-card combinations that give East and opening and West responding values than in case B) - in case B), RHO would basically have to have all the remaining high cards to have an opening.

 

There is also a third option - play ♠K, and if it's wrong, try to drop the ♥K.

[dellache]

Obviously I agree with the principle, but nevertheless I don't think it tells us to play the J here.

We have to compare what is more likely:

A) West ♠Q/East ♠A ♥K or

B) West ♠A/East ♠Q ♥K

Since I believe the trick one evidence that LHO has the ♦Q, in case A) there seem to a little more high-card combinations that give East and opening and West responding values than in case B) - in case B), RHO would basically have to have all the remaining high cards to have an opening.

 

There is also a third option - play ♠K, and if it's wrong, try to drop the ♥K.

I don't agree with my original (now edited) post which I wrote too fast and you are completely and obviously right about what we have to compare. My original post is a true syllogism because it doesn't take into account the numeric values of the case frequencies we wan't to analyse. I hope it will be clearer just below.

 

In details :

 

0. We suppose the ♠AQ are split.

 

1. We can analyse the board by taking 2 possible "events" into account :

EVENT-1 = East has the ♠Q

EVENT-2 = East has the ♥K

 

2. Putting that into frequencies we can "produce" a %-table (example below) :

           West HK    East HK
East SQ     C11=  6     C21=50
West SQ     C21= 19     C22=24

 

3. Now the GOOD reasonning is the following :

- when West has the HK (column 1) WE CANNOT FAIL because we'll make the Heart finesse ;

- so don't take column 1 into account and see what's left in column 2 : that's your (correct) reasoning and we should finesse the Queen if C21 > C22.

By changing theC21 and C22 in the example above, we can see why my OP is a syllogism.

 

4. The above figures were calculated using a simulation in which West may have ♦xxx only (which is debatable : in France that would be possible because we can lead xx(x) from 3 small). I also allowed West to bid 1♠ with ♠Axxxx and OUT, but that's extreme. I also allowed East to open 1♦ with Qxx x KQJxx QJxx. The figures tell you to play the Jack. East was dealt the ♦QJ at least.

 

5. If we are more strict with constraints (West has to have 6 HCP for instance), it's still in favour of the finesse of the Jack, unless we decide that both the bidding and lead tend to show ♦Hxxx by West. IMO the problem is partly about knowing the LEADING habits of EW.

 

6. Of course the initial play was wrong : declarer should have played the ♦Ace to avoid the problem, [2] Get to hand with a Club, [3] Play the Heart finesse. If the King is off, it changes nothing. But if it's ON, we can now change our plan and finesse the ♠K for +1.

 

I hope that this post is correct, for a change.

[Finch]

Obviously I agree with the principle, but nevertheless I don't think it tells us to play the J here.

We have to compare what is more likely:

A) West ♠Q/East ♠A ♥K or

B) West ♠A/East ♠Q ♥K

Since I believe the trick one evidence that LHO has the ♦Q, in case A) there seem to a little more high-card combinations that give East and opening and West responding values than in case B) - in case B), RHO would basically have to have all the remaining high cards to have an opening.

 

There is also a third option - play ♠K, and if it's wrong, try to drop the ♥K.

 

I assume you mean RHO when you say LHO

[cherdano]

I assume you mean RHO when you say LHO

Uh. I thought RHO played the ♦K at trick one. Either I misread, or Sathya edited the post, I guess the former.

[sathyab]

I don't agree with my original (now edited) post which I wrote too fast and you are completely and obviously right about what we have to compare. My original post is a true syllogism because it doesn't take into account the numeric values of the case frequencies we wan't to analyse. I hope it will be clearer just below.

 

In details :

 

0. We suppose the ♠AQ are split.

 

1. We can analyse the board by taking 2 possible "events" into account :

EVENT-1 = East has the ♠Q

EVENT-2 = East has the ♥K

 

2. Putting that into frequencies we can "produce" a %-table (example below) :

           West HK    East HK
East SQ     C11=  6     C21=50
West SQ     C21= 19     C22=24

 

3. Now the GOOD reasonning is the following :

- when West has the HK (column 1) WE CANNOT FAIL because we'll make the Heart finesse ;

- so don't take column 1 into account and see what's left in column 2 : that's your (correct) reasoning and we should finesse the Queen if C21 > C22.

By changing theC21 and C22 in the example above, we can see why my OP is a syllogism.

 

4. The above figures were calculated using a simulation in which West may have ♦xxx only (which is debatable : in France that would be possible because we can lead xx(x) from 3 small). I also allowed West to bid 1♠ with ♠Axxxx and OUT, but that's extreme. I also allowed East to open 1♦ with Qxx x KQJxx QJxx. The figures tell you to play the Jack. East was dealt the ♦QJ at least.

 

5. If we are more strict with constraints (West has to have 6 HCP for instance), it's still in favour of the finesse of the Jack, unless we decide that both the bidding and lead tend to show ♦Hxxx by West. IMO the problem is partly about knowing the LEADING habits of EW.

 

6. Of course the initial play was wrong : declarer should have played the ♦Ace to avoid the problem, [2] Get to hand with a Club, [3] Play the Heart finesse. If the King is off, it changes nothing. But if it's ON, we can now change our plan and finesse the ♠K for +1.

 

I hope that this post is correct, for a change.

 

Don't you also have take into account the fact that West thought the double of 2♦ was just ♦s whereas East meant it to be a Support Double ? If West led a ♦ knowing that his partner had ♠ support one might be inclined to play him for the Ace, as he might easily have led a ♠ holding the Queen.

 

Another point about the lead. When you have already supported your partner quite a few partnerships make an attitude lead rather than a length lead. When East plays the ♦ Jack, it could be consistent with West holding the King, in which case he's unlikely to have ♠ Ace. So for the ♠ Jack to be right, West must have led a ♦ from three or four small and hold the ♠Ace (and may be secondary ♣ honor).

[dellache]

Another point about the lead. When you have already supported your partner quite a few partnerships make an attitude lead rather than a length lead. When East plays the ♦ Jack, it could be consistent with West holding the King, in which case he's unlikely to have ♠ Ace. So for the ♠ Jack to be right, West must have led a ♦ from three or four small and hold the ♠Ace (and may be secondary ♣ honor).

I agree, and that is why we want to know EW leading conventions.

In France leading xx(x) is totally standard even after the 3D "support" bid.

If the "x" in your example is attitude, then West has to have the ♦K, and it changes everything.