Here's another very interesting piece for solo guitar by a Japanese composer, Serenade by Toshio Hosokawa :
I'm listening to it for the first time, so I don't really have an opinion yet, but I'm already attracted by it anyway. Some aspects of it remind me Takemitsu's writing for guitar.
There seem to be a lot of great music written for guitar in Japan nowadays (and I guess everywhere else. XIXth century is so cool)