Before you continue to post here, I would strongly suggest that you actually read the
forum rules (wiki) that you agreed to and accepted when you signed up here, specifically the part about our
piracy policy (wiki).
What you are asking is verging on violating those, and has already led to one of your threads/posts being put into the bin.
There are some add-ons around which allow access to free-to-air media from various Japanese providers, although in some cases there are geographic restrictions on them (e.g. requiring a Japanese IP address). Those that we support you will find in the video addons section of the built-in Kodi repo within our app.
What you are asking is basically how to access media which you may not be legally entitled to view (that you can only legally access via a paid subscription or a service like cable). We cannot and will not assist in such illegal access, based on the already mentioned stance we have against piracy.
Some legal providers will provide a playlist (the M3U playlist you mention) giving access to their legally distributed sources once the subscription has been made and paid. Those may be used via IPTV Simple to access the channels in the playlist. We do not support random playlists that may have been obtained from other sources, as they frequently make use of illegally sourced media stored on temporary servers which tend to very quickly be found and removed by the legal copyright holders of the media.
Please consider this further, along with some of the other links in my signature below.
