Hi Makoto, the
Japanese forums have been created! You can view them here:
https://igpmanager.com/forum-index/39
Also, please be patient to let the forum populate as iGP Manager has only just released the Japanese translation, and iGP Manager is extremely new to the Japanese market. It will take time to build an audience and for some of them to find the forum. We would really appreciate it if you could refer your friends and help to populate the new forum!