For you as a professional, how important to you is studying the games played by other professionals?

Do you look at older or historical games (ie. from players like Cho Chikun etc., or further back to Shuei, Go Seigen and so on), only modern game,s or none at all? And when you're looking at these games, are you only looking for opening / joseki trends or any deeper insight?

I've sometimes read of certain professionals (when in training) heavily studying many games of a really strong professional like Go Seigen (or for pros of Go Seigen's era, Shuei): what do you think of this sort of head-on technique for pros?

To clarify, I'm not asking about amateurs studying pros, just about how the technique is applied in the professional community.

This question was answered here.

Huge thanks to Guo Juan for that.