[bluto32]

I've been going through a variety of hands on Bridge Master, and am surprised by the recommended line of play in the spade suit for Beginner Hand A20. The main teaching point concerns managing entries to dummy carefully in order to be able to finesse twice, but I am not sure that is necessary.

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The contract is 6♠ by South with no bidding from East/West. West wins his ♥K lead and continues with ♥Q.

My initial attempt was to finesse against the ♠K once, and then go for the drop on the second round. But Bridge Master penalises this line of play, instead requiring you to take the finesse on the second round as well.

Once the first finesse succeeds and East has played low on the second round, isn't there more "space" for the king to lie in West's hand, and the drop therefore a little more likely to succeed than a second finesse?

I am wondering if this is an error in Bridge Master or I am overlooking something...
Bluto


P.S. Another thought: the situation at this precise point (in the second round of the suit) appears to be analogous to the "Nine never" rule below when holding nine cards with the queen missing. After cashing the ace, the recommended line of play is to hope to drop the queen on the second round, rather than go for the finesse:

♠ 4 3 2

♠ A K J 10 9

[Stephen Tu]

 bluto32, on 2019-May-06, 03:29, said:

Once the first finesse succeeds and East has played low on the second round, isn't there more "space" for the king to lie in West's hand, and the drop therefore a little more likely to succeed than a second finesse?

West isn't going to duck first round from Kx as it is the setting trick. Your vacant spaces theory only applies if West is held at gunpoint and required to play low the first round.
You'd prefer to win against both Kx and Kxx onside, not only Kx onside.

[bluto32]

Thank you! I failed to spot the obvious fact that West hasn't had the chance to win the first trick in the "Nine never" case.
Bluto

[apollo1201]

 bluto32, on 2019-May-06, 04:06, said:

Thank you! I failed to spot the obvious fact that West hasn't had the chance to win the first trick in the "Nine never" case.
Bluto

Actually the recommended line of play loses when East or West is singleton D and ruffs your 2nd attempt to reach dummy, while banging down the A would have dropped the remaining trumps.
But 3-1 break of S is more likely than the 5-1 break of D *and* 2-2 trumps.

[rmnka447]

 apollo1201, on 2019-May-06, 10:11, said:

Actually the recommended line of play loses when East or West is singleton D and ruffs your 2nd attempt to reach dummy, while banging down the A would have dropped the remaining trumps.
But 3-1 break of S is more likely than the 5-1 break of D *and* 2-2 trumps.

Just in rough numbers --

3-1 break with 4c cards is a 50% probability overall with nothing known. Since RHO can only be 3-1 that's a 25% probability.

5-1 break with 6 cards is about 14.5% probability X approximately 40% probability of 2-2 break in trump since both must be true to go down. That works out to be about a 6% probability.

So making the recommended play adds about an additional 19% to the likelihood of making the contract. That's a good chance to take.

[pescetom]

 rmnka447, on 2019-May-07, 08:50, said:

So making the recommended play adds about an additional 19% to the likelihood of making the contract.

That additional 19% corresponds to 44% instead of 25%, so in relative terms it improves chances by 76%, in any case a huge difference.

[apollo1201]

 pescetom, on 2019-May-07, 09:22, said:

That additional 19% corresponds to 44% instead of 25%, so in relative terms it improves chances by 76%, in any case a huge difference.

Thanks guys for adding the figures to my analysis. 😃