Is there any? I mean, now in Legion we've seen a lot of amazing Chinese guilds but I have never heard of any Japanese guilds, competitive or otherwise. Come to think of it, I have never heard about WoW being played in Japan, or any sign of Japanese communities in the game at all.
Is WoW even available there? A quick google shows a few years old posts that would indicate there is no Japanese client but is the game in the english version available to them at all?