smerriman, on 2019-August-03, 18:58, said:
GIB leads the king because it assumes that declarer will know it is a singleton and drop it under the Ace; therefore it will never take a trick. This of course is silly in reality, but it's just how the robots work.
Adjust your sim to assume a 'normal' line of trump play and you'll probably discover that the king costs you the contract many times that double dummy says it makes no difference.
I did say it wasnt the top lead
Ace diamonds first
Clubs next
Then the rest fairly equal with not much chance of any setting the contract.
But it was a 5 minute back of the envelope sim. I'm not in the sim business and dont pretend to be
All I said was that it is seems to be the way the bot plays with an uneven trump break to try to give trump control to partner. I have noticed it before
Note. Here are the chances of making 4+ tricks (almost 0). I just reran it and it given there is so little difference it has a slightly different order
The above results were relating to average tricks, not setting the contract
Spade 0.056
Club 0.054
Ace D 0.05
KH 0.044
Small D 0.043
95% CI Approx +-0.012
Edit For completeness this is the lead order to maximise expected number of tricks
Average number of tricks maximised by leading Ace D
Ace D 1.91 tricks
Small C 1.69 tricks
QC 1.66 tricks
Spade 1.65 tricks
K H 1.59 tricks
Small D 1.58 tricks
95%CI Approx +- 0.07
But as I said it was a 5 minute (3 to write and 2 to run) basic script and 1000 deals using bdeal. Nothing fancy in the script at all. Just a few constraints and double dummy
I don't spend much time looking at sims although simulating leads is fun to compare with expert theory. I don't have much time left to explore that. I'm more interested in the statistical theory and game theory of competitive bridge - but I hasten to add I am a disinterested amateur, unafiliated to anyone other than myself and my (almost retired) business is not related to bridge in any way. This is a nice relaxing way for me to keep my mind active in the absence of (lack of motivation to chase any) serious contracts