Two way finesse

[MickyB]

[hv=d=s&n=s94hkq5da763ckjt5&s=sqt5ha2dk954ca962]133|200|1N:3N

West leads the 2♦, which you can assume is 4th highest. Who is more likely to have the Q♣, and how much more likely are they to have it?[/hv]

[inquiry]

This is easy or this is hard. If the only assumption you can make is your lHO has 4D to his parteners one (we will see the diamond on the right), that means there are more slots to hold the club queen on your right than on your left. The math suggest rho has a 57.1% to hold the club queen.

 

However, West didn't lead a major. And with four in either of those suits you would assume that he might lead that than from a broken QTxx type diamond suit. So that might mean ten major cards with rho, to only six (at most) with left hand guy... that will drag the odds way back down.

 

This game gets hard when you do all this conditional math thinking... :-(

[mike777]

Ben gives you the expert thinking. Here is the non expert thinking.

 

1) LHO will lead their longest suit.

2) If we assume LHO has exactly 4D they do not have a longer suit.

3) If they had a 4 card major they would lead that over a minor.

4) If they were 4-4 in the minors, they may have lead a club rather than a D.

5) I will play 3H to see what happens.

6) Assuming LHO follows to 3 hearts I will assume LHO is 3-3-4-3 or has 4-4 in minors and play LHO for Q of clubs.

7) over weak NT LHO may have made a 2 suited 4-4. 5-4 or 5-5 bid and did not.

8) I will win first trick with A of D and cash ace of clubs first just in case stiff Q of clubs is with RHO.

[Guest Jlall]

I completely agree with Mike. Rule of empty spaces is NOT as strong an inference as them leading their 4th best diamond. With 4M and 4 diamonds they would usually prefer the major on this auction. I play opening leader for the CQ.

 

Edit: agree with mike and ben, sorry didnt mean to leave ben out

[inquiry]

Ben gives you the expert thinking. Here is the non expert thinking.

I gave you the mathematician way of thinking (just about diamonds), then showed that thinking about just diamonds was wrong. So of course, i didn't give the "expert" solution... all i did was point out why the apparenlty simple math solution is way wrong.. :-)

[Winstonm]

I completely agree with Mike. Rule of empty spaces is NOT as strong an inference as them leading their 4th best diamond. With 4M and 4 diamonds they would usually prefer the major on this auction. I play opening leader for the CQ.

 

Edit: agree with mike and ben, sorry didnt mean to leave ben out

Well Zia just got you; he led low from the 52 doubleton. :P

[JSilver]

It would be nice to know what card East played at trick 1. If it was the ten, then West led a suit headed by QJ. Perhaps he thought it looked more promising than his other 4-card suit. It's even conceivable that West is 4-4-4-1. He might have ♠Kxxx, say, and hopes to use the ♠K as an entry to cash diamond tricks once they're established.

 

I suppose players tend to lead a major, but how strong is that tendency? Surely there are other considerations.

[MickyB]

Sorry - East played the J♦.