Restricted choice vs restricted entry

[manudude03]

Suppose you had a restricted choice situation and it occurred in such a way that if you went for RC and were wrong, it would cut off other options for making the contract. do you still go with RC or do you go against it so you still have the other chance?

 

An example (hopefully not too cooked) below.[hv=d=s&n=sahk64dt432c76432&s=skqhaqjdak965caqj]133|200|Scoring: IMP[/hv]

 

Suppose you were in 6NT by south on the ♠7 lead, when you play a top diamond, the ♦J drops on the left. How would you play it?

 

* Not a real hand, just made up to illustrate the question.

[CSGibson]

I don't think this is a real restricted choice situation because the Q or J would be a choice from QJx as well as QJ or Q or J, or at least that would be the case against top notch defenders.

[Cyberyeti]

I think this example is in fact fairly typical in that it's not that simple and there is a way of combining chances in some way.

 

Win the spade, play a club to the Q at trick 2.

 

if it loses, play restricted choice.

 

If it wins, you have a choice (there is no guarantee that the K is in fact right). Either cash the AC, if the K drops either side, you have 12 tricks, and if it doesn't, you hook the diamond, or you play diamonds from the top, and hook the club if they don't break.

 

As will happen in many cases, the right line may depend on how often you think LHO will fail to win the KC if he has it.

[ONEferBRID]

Even if you picked up the entire Diam suit, you still need the Cl finesse onsides for a 12th trick.

So, you can afford to lose a Diam, retaining 2 entries to dummy ( ♥ K and ♦ 10 ) for 2 Cl finesses:

 

Tricks will be 2s, 3h, 4d, and 3c .

 

There is an extra chance if K x doubleton is onsides,

Take Cl finesse as trick 2 ( as Cyber... suggests ) .

If it wins, plunk down the ♣ A .

If the K drops your tricks are:

2s, 3h, 2d, 5c .

 

If the ♣ K doesn't fall, you have to pickup all the Diam.

[CSGibson]

Even if you picked up the entire Diam suit, you still need the Cl finesse onsides for a 12th trick.

That is not right, obviously.

[PhantomSac]

Manu, basically it comes down to a math problem.

 

On this hand, ignoring the chance of a falsecard from QJx, if you play diamonds from the top you make on QJ doubleton of diamonds, or the club hook.

 

If you go for restricted choice you make on Hxx of diamonds, or Kx of clubs onside (or stiff king).

 

Since Hxx of diamonds is ~twice as likely as QJ doubleton, and the club hook onside is 50/50, that is ~ a wash. Which means playing restricted choice gives you the additional chance of stiff K or Kx of clubs onside.

 

As someone else said, there is the possibilty that LHO has QJx of diamonds and falsecarded. Still Kx or stiff K of clubs onside is not insignificant, so they'd have to find that falsecard a huge amount of the time that they have that combo to make it percentage to bang down the diamonds.

 

Finally, as someone else said, there is a problem with your example hand...you should clearly win the spade lead and hook the club. Basically you do something productive with your SA entry (take a finesse), rather than something useless (play a diamond, when you could have played one from your hand anyways).

 

But in general the process is always the same, just calculate which combination gives you the highest chance of success. In general remember that restricted choice is almost 2:1 as likely, so in a pure example if you lost a finesse because of playing restricted choice, the plays are almost even.

[rfp]

If the club finesse wins at trick two, you can cater to all

your best chances. Cash a top diamond; if LHO drops an

honor, cross in hearts to finesse in diamonds, then you

can later finesse again in clubs (♦10 entry).

 

--

Richard Pavlicek

Web site: www.rpbridge.net

[manudude03]

Finally someone answered what the topic was really about. I was in a bit of a rush when I posted it. I suppose the question was "How good does the alternate chance have to be to give up on RC?".

 

Remind me not to make example hands until I'm sure of it :). The only purer hand that came to mind was to give declarer an even stronger hand.

 

[hv=d=s&n=saxht64dt432c7642&s=skxhakqjdak965caq]133|200|Scoring: IMP[/hv]

 

is probably a better example of what the main point was.

[PhantomSac]

"How good does the alternate chance have to be to give up on RC?".

RC is almost a 2:1 favorite, so the alternate chance should at least double your chances to make up for that.

[nigel_k]

Finally someone answered what the topic was really about. I was in a bit of a rush when I posted it. I suppose the question was "How good does the alternate chance have to be to give up on RC?".

 

Remind me not to make example hands until I'm sure of it :). The only purer hand that came to mind was to give declarer an even stronger hand.

 

Dealer: South Vul: ???? Scoring: IMP

♠ Ax ♥ T64 ♦ T432 ♣ 7642 ♠ Kx ♥ AKQJ ♦ AK965 ♣ AQ

 

is probably a better example of what the main point was.

I don't think there is a generic answer - you have to work each one out.

 

In your second example above, on a spade lead the club finesse doesn't help unless you take it at trick two. If you win in hand, cash a diamond, then cross and take the club finesse you are still down if you have to lose a diamond.

 

On a heart lead you can use the spade entry to play for restricted choice in diamonds and still have ten of diamonds as an entry for the club finesse later.

 

If we switch the ten and five of diamonds and assume a heart lead, I think it produces the scenario you were actually asking about. In that case you can cash a second diamond and use the spade entry to finesse clubs [A] or use the entry to finesse diamonds and give up on clubs .

 

A is better when QJ doubleton of diamonds are on your left regardless of clubs, approximately 0.4 * 1/6 * 1/2 = 0.0667

 

B is better when LHO has either singleton Q or singleton J and the club finesse is off, approximately 0.25 * 1/2 * 1/2 = 0.0625

 

So A is best. If they might falsecard from QJx it is even better.