Trapped Bishop Test Position

[brianr]

There has been code in Tinker for a long time avoid trapped bishops, but a couple of recent games have identified a weakness.
In the position below, Tinker sees the trap when the bishop is on h7, but during the search the bishop ends up on g8, and the penalty is not currently set.
Unfortunately, it did not see deeply enough to avoid the eventual loss.
Other engines may also have this weakness.

[D]8/3r1ppB/4pk2/8/p7/PbR1KP2/6PP/8 b - -

[bob]

There has been code in Tinker for a long time avoid trapped bishops, but a couple of recent games have identified a weakness.
In the position below, Tinker sees the trap when the bishop is on h7, but during the search the bishop ends up on g8, and the penalty is not currently set.
Unfortunately, it did not see deeply enough to avoid the eventual loss.
Other engines may also have this weakness.

[D]8/3r1ppB/4pk2/8/p7/PbR1KP2/6PP/8 b - -

I've always included g8 with h7 for that very reason in my test in Crafty's evaluation...

[Martin]

I think it depends on how far you want to go with the static evaluation of such problems.

I do have code for this nasty situation:

[D] 8/1pp1p3/5p2/4nk2/7B/1P1P2P1/1KP5/8 b - - 0 1

But not (yet) for this:

[D] 4B3/1pp3bp/4k1p1/8/8/1P6/1KP3PP/8 b - - 0 1

[Martin]

And I don't need to because the position is illegal.

Okay, let's play c3 first ...

[D]4B3/1pp3bp/4k1p1/8/8/1PP5/1K4PP/8 b - - 0 1