[cochrun]

Playing sets of 4 deals on BBO I got the cards shown. E passed. As S I opened 1NT, W bid 2 and my robotic partner N jumped to 4♥. I passed, thinking that N had a bunch of hearts and some good points. Please explain how the robot came to the conclusion to bid 4♥ with only 5 hearts and 6 HCP?

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[akwoo]

What the robot does in this situation is randomly generate 100 hands with 15-17 points and balanced and decide what the best bid is for them opposite these 100 hands.

In this case, I think the robot actually made the right bid. If you have ♠763 ♥KQ4 ♦A9852 ♣AQ3 then 4♥ is about 80% likely to make. Keep in mind the robot doesn't have any invitational sequences available here, and 3♥ (which is forcing, choice of games) would not be a good bid since it doesn't want to be in 3N even if you only have 2 hearts. Being vulnerable, you want to be in game even if it makes only 40% of the time.

[smerriman]

akwoo, on 2016-September-02, 21:29, said:

What the robot does in this situation is randomly generate 100 hands with 15-17 points and balanced and decide what the best bid is for them opposite these 100 hands.

Only if it were an advanced robot - sounds more like the OP might have been playing the free 'Bridge 4', where no simulations are done.

However, even the basic bot will add 3 points for the spade void. 4♥ seems like a reasonable choice.

[1eyedjack]

smerriman, on 2016-September-02, 21:40, said:

However, even the basic bot will add 3 points for the spade void. 4♥ seems like a reasonable choice.

Unless 3H is forcing. Which I think it is, as robots play Leb

[BillPatch]

1eyedjack, on 2016-September-03, 04:40, said:

Unless 3H is forcing. Which I think it is, as robots play Leb

akwoo made the observation that 3H was forcing and a choice of games. 4H was still "the best bid." The fact that the robot failed to make the proper simulation to determine the merit of 3H when 3NT will never make on a fit-less sub minimum and still made "the best bid" is a credit to the programmers.

[1eyedjack]

He expressed the point. I do not have to agree with it. And in point of fact I do not. If partner chooses 3N (or 3S in doubt) over 4H having only 2 card support for a 5 card suit headed by Jack I expect to support his judgement more often than not.

[mycroft]

What is the chance that, with a spade void, 3♥ is going to lead to 3♠, and then 4♥ to 4♠ (or then 4♥ to a higher-information pass) and be right? What is the chance that, with a spade void, 4♥ is going to lead to 4♠ and be right? Which is more likely?