Is there a reason komi can't be global?

[Recursing]

https://github.com/pasky/michi/blob/3c491058db8d4a8cdca7efb2a2323eb8cc913051/michi.py#L1089

Can't the komi be set as a global variable (like N), and updated via gtp_io? It's read only in score and rewritten only in gtp_io, also would be clearer to have the default value on top, maybe with a comment that says it can be changed in gtp mode

If it's ok I can make a quick pr