# Computer Scoring for Go

Hi everyone!
I am engaged in developing Computer Go. I want to use Monte Carlo Tree Search for my algorithm. But my problem is scoring. I know about Territory and Area Scoring. Let’s consider Territory Scoring. How can i score the number of empty points only my stones surround? So if I move my stone in opponent territory this territory will became neutral. When i play against computer (Fuego, igowin, this site) i see that this opinion is wrong (there are territory with black and white neighbors and, for example, all territory became black and all white stones here became prisoners(but no one take them away from board)). Could someone explain me this, or give some algorithm for scoring like auto score on this site? I use dfs for detect that area surrounded only by black or only by white stones.
Sorry for my bed English.

Thanks.

Hi www3,
I have little experience in programming, but I hope I can at least clear up some of your confusion about scoring the empty points (territory) that have both black and white surrounding them in some way. There are 3 possibilities locally, of course: seki, territory for black, or territory for white. As you noticed, when computer players on OGS score there will be some situations where, for example, a small amount of black stones surrounded by a larger white framework will be considered prisoners for white even though they remain on the board (and you will see a white mark on the black stones). The black stones in that situation are considered “dead stones” and they count as captures; the territory that lies under the dead black stones are also counted as territory for white (So in some sense, a dead stone is worth 2 points in scoring).

How do you program a Computer Go player to recognize dead stones? Overall, you may have the computer simulate moves locally as if the game were to continue with both players controlled by a strong computer player. Then in this simulation you will see what stones would be captured if the game were to continue, these are your dead stones. Even in professional play there can be some disagreement about dead stones, so it will be good to offer the player an option to continue playing if they do not like the result of the computer’s scoring. Lastly, I wanted to talk about seki. When you have the computer simulating moves after the game officially ended, there will be some situations where the only way both black and white can prevent their stones from being captured is by passing, this will be seki and the territory scores for neither player. Hope this helps!

~Weston

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Thanks a lot

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