[sakuragi]

<Here is the hand>

Trick 2 LHS follow DJ
Trick 3 LHS follow DT

[mikeh]

We need LHO to hold 3 diamonds to have any play: if RHO has 3 diamonds, we cannot make.

Therefore the odds are 3=2 that LHO has the King.

Since he will never play the King on the first two tricks, it is unsafe to infer a restricted choice scenario. With KJ10, he has to play the J and the 10, and the order in which he plays them is, in theory against a perfect defender, irrelevant. The fact that he did not play the King earlier doesn't change the a priori odds that he has the King.

In real life, when a non-expert plays J10, I would be inclined to think that there is now a better than normal chance of J109, simply because I think that non-experts often over-think carding in an effort to be tricky.

Personally, if playing against someone whose game I don't respect or who I think doesn't respect my game, I would usually play 9 and then J, as my 'tricky' plays.

I once, many years ago, read this situation to make a 6H contract, and my expert partner later complimented me on my table feel while pointing out that it was probably the wrong technical play

[gszes]

Stupid game grrr I am unsure. we need lho to hold 3 dia and rho to hold 2 dia and the way the hand was played rho would KNOW it was safe to part with the 9 if they began life with the 97 thus making a strong case for restricted choice. The 7 is required from K7 but 97 would have been 5050 which seems to ME (sigh) the combination of events would make it higher that rho began with K7 rather then merely going with the longer suit has the greater chance of holding the K. I would have played low and gotten lucky?? Why isn't there a high level mathematician around when you need one???

[mikeh]

Gazes: while RHO might, but usually wouldn’t play the 9 from 97, it is a moral certainty that very few LHO’s would play the J10 from J107


That it costs nothing is beside the point. Bridge is played by humans and I doubt that one player in a hundred would card that way

And on this hand it is very relevant. Picture declarer with A9x

[HardVector]

It's not restricted choice, that involves just missing 2 relevant cards. Here you are missing KJT97. The only thing you have to get right, is who has the K? If east has K97, you lose, period. If west has KJT9, you lose, period. So you have to play for either KJT with west, or K7 with east. Here, you have to know how the robot plays. I'm unfamiliar with it, so I'm not going to comment further.

[Stephen Tu]

Restricted choice applies (as it does whenever an opp has choice of plays from equal honors, whether 2 or more than 2 equal honors), right play is the Q, and it's not close.

• RHO shouldn't play 9 from 97, or H from any H7. When LHO follows with the third of the equals, if he has played high he has given declarer with the 8 a no lose proposition by playing the Q.
• LHO with KJT *has to play the T and J in some order*.-LHO with JT9 *can conceal any of the 3*.This is the essence of restricted choice. KJT and had to play JT is 3x more likely than JT9 and chose to conceal the 9.

The other way to look at it is that assuming LHO plays 2 of (J/T/9), playing the Q picks up J7/T7/97 offside, and only loses to K7 offside.

[rhm]

deleted

[kenberg]

Perhaps the comment by mikeh "Personally, if playing against someone whose game I don't respect or who I think doesn't respect my game, I would usually play 9 and then J, as my 'tricky' plays."should be explored further.

Suppose mikeh is Lho and plays the 9 and then the J. Declarer thinks to himself: "If Mike started with KJ9 he would have had to play the cards in that order since, for all he knows, I have the T and, if I do, then dropping the J under the A will make life easier for declarer. Therefore, since Lho would have to play 9 then J when holding KJ9 but had a choice when holding JT9, I will play Lho for KJ9"
Ok, if we agree that a good play from JT9 is to play the 9 and then the J to encourage declarer to put up the Q, what are we to make of the fact that Lho didn't do that on this hand? If 9 then J is a good play from JT9 then should the play of the J then T be seen as evidence that Lho does not hold the JT9?
Declarer reasons: Surely a good played such as mikeh would play 9 then J if he had JT9, he did not do that, therefore mike has the KJT so I will put up the Q. Oops.
I happily confess to some confusion, but this seems to me to be one of those spy versus spy things. I always treat the robots as if they were human but maybe the question should be: Is mikeh smarter than a robot? No insult intended to either mike or the robot.

[miamijd]

Stephen Tu, on 2019-May-07, 17:05, said:

Restricted choice applies (as it does whenever an opp has choice of plays from equal honors, whether 2 or more than 2 equal honors), right play is the Q, and it's not close.

• RHO shouldn't play 9 from 97, or H from any H7. When LHO follows with the third of the equals, if he has played high he has given declarer with the 8 a no lose proposition by playing the Q.
• LHO with KJT *has to play the T and J in some order*.-LHO with JT9 *can conceal any of the 3*.This is the essence of restricted choice. KJT and had to play JT is 3x more likely than JT9 and chose to conceal the 9.

The other way to look at it is that assuming LHO plays 2 of (J/T/9), playing the Q picks up J7/T7/97 offside, and only loses to K7 offside.

You are quite right, except if you are playing against GIB, in which case the right play is to lead low out of hand, not Ace. GIB will almost never duck the King on the first round (it will duck if you play Ace first), so if GIB doesn't fly King, play low from dummy and hope the King is doubleton.

Cheers,
Mike

[gszes]

mikeh, on 2019-May-07, 13:43, said:

Gazes: while RHO might, but usually wouldn’t play the 9 from 97, it is a moral certainty that very few LHO’s would play the J10 from J107


That it costs nothing is beside the point. Bridge is played by humans and I doubt that one player in a hundred would card that way

And on this hand it is very relevant. Picture declarer with A9x

They cannot have started with the JT7 since the 7 appears first trick and surely tossing the J from JT7 can never hurt unless you are bending too far over the table. Once the 7 appears from partner what is the best play to dissuade declarer from playing p for Kx? Peeps toss honors against me like snowflakes I gotta start playing against an easier crowd:)) but I like your point

[Stephen Tu]

gszes, on 2019-May-08, 15:12, said:

They cannot have started with the JT7 since the 7 appears first trick and surely tossing the J from JT7 can never hurt unless you are bending too far over the table. Once the 7 appears from partner what is the best play to dissuade declarer from playing p for Kx? Peeps toss honors against me like snowflakes I gotta start playing against an easier crowd:)) but I like your point

If declarer going to guess right, they going to guess right. But you *want* them playing for Kx offside. You own them by simply not screwing up by playing K 2nd round whenever you hold onside KJT, KT9, KJ9, K97, KT7, KJ7, and getting an undeserved 2nd trick whenever they outsmart themselves trying to play for K? offside.

As declarer, the whole point of playing for the percentage restricted choice plays is that you don't have to play any guessing games, any spy vs spy games. You simply decide beforehand that you are picking up 6 of the ten relevant combinations and don't let the opponent's carding dissuade you when those combos are still in play, knowing this is the best you can do, and other strategies risk worse.

On this particular combination, you can't make any exploitative play for any advantage, unless it is from a player that pops K from K?? thrid onside for no particular reason. If you decide that someone "always" plays JT from JT9, if you cater to that, then you lose all the KJT onsides for a wash.

This is unlike the AKT9xx vs xxx combo, where if you knew for 100% certainty that someone always falsecards Q from QJ tight offside you can exploit them for a very tiny percentage gain that isn't worth it if you are the tiniest bit unsure about your target.

[sakuragi]

yet another ....

https://www.bridgeba...ST%7Cmc%7C12%7C

note 2 new poll questions (could only add 1 more poll)
is the 6h hand another restricted choice?
is the 6d hand or 6h hand a stronger restricted choice case?

[Stephen Tu]

On your 6H hand, restricted choice principles still apply, but playing for the stiff honor is a bad play against decent opponents, because of the possibility of a falsecard from JTx.

Basically, if RHO *always* plays low from JTx, stiff J + stiff T > JT tight (restricted choice reasoning applies, you either count total of all these combos ignoring which honor was played, or you pick the honor actually played and half the frequency of JT tight), and you should hook.

But against an RHO who is capable of playing an honor from JTx something like at least 23+% of the time, now playing for the drop and picking up all of JT doubleton + JTx is more than stiff honors.
If you are playing against beginner level opponents who you think might only play honor from JTx something like 10% of the time (or anything <= ~22%), then hook is still better.
As defender look for opportunities to play honor from JTx when it can be done without cost!

[sakuragi]

gib does play high card early in defence, though may not be for same purpose.
so as the saying goes ......

i would rather be lucky than good

[sakuragi]

and here it comes again ....

{comments}

---

hand

At trick 7 do you put up Q and why? restricted choice?

Here is the other result of the board

https://webutil.brid...519277-R1-B6-I1

[Stephen Tu]

Restricted choice yes, and yes you put up the Q against best defense. You win vs KT4/KJ4 East, losing vs JT4 East. That's 2:1 in favor of putting up Q.

On the other hand if LHO drops T or J, play LHO for KJ/KT doubleton, 2:1 in favor vs playing for JT tight.

Now whether robots are terrible enough that different strategy is called for, I don't know.

[sakuragi]

what about this one?
On trick 6 when u see SJ from your right?


https://www.bridgeba...CC9%7Cmc%7C9%7C

[Stephen Tu]

sakuragi, on 2020-April-26, 07:30, said:

what about this one?
On trick 6 when u see SJ from your right?

If and only if west was equally likely to lead A from AJ/AT/AK, RC would apply and you should play Q. But in reality west should be very reluctant to lead from AJ/AT, as he only needs Txx/Jxx from partner to outright blow a trick, so your play is right IMO. Plus on this hand East has already shown enough that West is supposed to have the SK to justify the bidding.