About --relative-rank?
https://github.com/CGLemon/Sayuri/issues/18

"The range of --relative-rank should be between 0~25. The higher value should be stronger and only work on the 19x19 game. Here is how it works.

We transform the relative-rank into the number of active children at the root node. The root will randomly select this number of children and prune other non-selected children. For example, the root randomly select 23 children at the first move if the relative-rank is 0.

The number of playouts option will significantly affect the strength, because the root may prune all high priority move. The policy network does not work in the case. The tree search could keep the quality of moves."