GIB's rules of leading

[thorvald]

I am still trying to figure out if there are any rules for what card to lead thru declarer or just later in the play, just like the rules for the opening-lead.

 

The bot got this East hand

[hv=pc=n&n=shkq7dkt7432ckjt9&e=sq952hjt852d96cq2&d=s&v=e&b=3&a=1sp2dp2sp3cp3nppp]266|200[/hv]

 

Now partner leads ♣4, and declarer fails and uses the 9.

 

Now the bot figures that switching to ♠ is right (as often seen a switch to shortage at dummy)

 

But what card?

 

Now change the bidding a bit

 

[hv=pc=n&n=shkq7dkt7432ckjt9&e=sq952hjt852d96cq2&d=s&v=e&b=3&a=1sp2dp2sp3cp3dp3hp3nppp]266|200[/hv]

 

 

Same lead, and same error by declarer, and GIB again decides to play a ♠ in the two situations

 

What is interesting that GIB did not play the same ♠

[smerriman]

There aren't any rules, at least not in this situation (but perhaps others like leading from a sequence). It's not bidding related, it just sees 2 and 5 both score identically and chooses one at random.