A question of probabilities?

[Simplicity]

[hv=d=e&v=b&n=sjt8763hk97djtca9&s=sa5haqj65dq52ckq6]133|200|Scoring: IMP

4♥ by South

T1: ♦6 T A 2

T2: ♦8 5 K J

T3: ♦3 ?[/hv]

 

You have arrived in 4♥ on the auction 1♥-1♠-2NT-3♣*-3♥-4♥

 

The opponents are playing 2nd and 4th leads, what's the most probable route to success from here?

[helene_t]

I would ruff with the King. Now I make it if hearts are 3-2 or the ten is sec.

 

If I ruff with the 9 I make it when East had more than two diamonds (very hard to assess that probability, should be very low if he's about the same level as I, but could be substantial if he's a novice or an evil expert) and also when East doesn't have ♥T (less than 50% chance because of empty spaces and also because continuing diamonds is less attractive without that card).

[Codo]

There are three lines:

1. Let the diamond run: No good, you can improve your line with line two, because you have no good discard- this is just better when East has 5 Hearts and you can pick them up.

 

2. Ruff with the nine. This wins, when West has 5 or less Diamonds and or if he has 6 and the ten of Heart.

 

3. Ruff with the King wins, if hearts are 3-2, or the ten of H is singelton.

 

If opps lead 2.4. West may have 6 diamonds. If they lead 2.4.6. he does have 5 diamonds, because he had lead the 3 from six at the first trick. I would ask.

 

I won´t read too much in the attack and the continuation of Diamond. After all with Kxxxx a lot of people would prefer to lead this suit compared to some jack high in Clubs. And to return pds suit before the loosers can be discarted looks good whether you own 1,2 or 5 Hearts with or without the Ten.

 

I am still not sure about the best line, but I guess I go with the 9.

[cherdano]

I would ruff with the King. Now I make it if hearts are 3-2 or the ten is sec.

 

If I ruff with the 9 I make it when East had more than two diamonds (very hard to assess that probability, should be very low if he's about the same level as I, but could be substantial if he's a novice or an evil expert) and also when East doesn't have ♥T (less than 50% chance because of empty spaces and also because continuing diamonds is less attractive without that card).

I think a decent LHO may have many simpler reasons than faking a trump promotion to play another diamond. Probably she has ♠K or Q, so doesn't want to play a spade, she can see a club doesn't do anything good and a trump is risky, so maybe she is playing another diamond just in case declarer has 4 of them.

 

I also disagree that LHO is less likely to try the trump promotion when holding ♥T (assuming diamonds are 6-2). If she has ♥T, she just needs one higher honor with partmer to make the trump promotion successful, if she doesn't, the trump promotion needs one higher honor from partner AND a misguess by declarer.

[bhall]

6-2 vs. 5-3 is 26%. ♥10 (or any unknown card) on the right is about 11/18. So the ♥9 will lose 16.6% of the time when ♥ are not 5-0, plus an additional 3.9% when they are. When the ♦ are 5-3, ♥10xxx in either hand happens about 4/5 of 28.2%, or 21%. So, the first line fails about 20.5% and the second, about 24.9%. Not a huge difference.

 

Of course, this ignores the likelihood of a lead from Kxxxxx and of a return from A8x, given the auction and dummy.

[skjaeran]

Without studying the odds in depth I'd ruff with the 9.

 

Btw, where I play I'd ruff with the king knowing the suit to be 6-2, since 'all' lead lowest from 5 and 4th from 6 vs a suit contract.

[Halo]

On an approximate calculation I make it so close that the odds don't help and you have to go by impression.

 

I'd ruff with the King.

[Fluffy]

What about playing ♦Q at trick 2?, I wouldn't b quick enough to do it, but it maybe was a good idea.

[Halo]

Nice play, you are a trick short but with more room to check trumps.