[pescetom]

Another day in the office for GIB

It's not Robot East's fault that human partner bid NT and wrote off the grand slam.
But I wonder if even Anthias and Bird would approve of any lead but hearts by Robot North?

[smerriman]

By my calculations, A+B would say:

card / probability of beating contract / average tricks taken:

S3 - 31.6% - 3.98
HA - 21.8% - 3.56
H6 - 35.2% - 3.84
D7 - 26.3% - 3.77
CJ - 22.2% - 3.59

So they would indeed recommend the passive lead at MPs - but the heart at IMPs.

Of the 1000 deals I generated, if the choice was solely between spade + heart, a heart was strictly necessary to beat the contract on 146, while a spade was strictly necessary on 110, so I can see a limited-simulation GIB that uses A+B's logic going either way.

[akwoo]

Against humans not known to bluff (which is most of them), there is no way I would lead a heart at MPs.

Unless you've got a reputation for doing it, bluff a stopper does really work.

[LBengtsson]

There is no reason for North not to lead the ♥ suit. As beginners we are told to lead from our longest suit against no-trump contracts. The vulnerability might have stopped South overcalling 1♠ had he had a overcall, but making a passive lead here is crazy imo. But robots do crazy things