I became interested in Japanese popular music around 1985 or so when i worked at a record store and was the import buyer. I was routinely exposed to album release pitches (mostly by mail) from representatives of distributors and labels. So reading about these various groups i started to form an interest.
Also around this time i was listening to Art Rock a lot, and Henry Cow guitarist Fred Frith was producing a lot of Japanese bands. Other Western artists were getting involved in the Japanese scene too. XTCs Andy Partridge, Thomas Dolby, Robin Scott (the guy behind the smash hit "Pop Music"), Adrian Belew, the list goes on. So whenever i'd see a familiar name on a Japanese release, my interest was further piqued.
One of the first Japanese artists/bands i bought records by was Yellow Magic Orchestra (or YMO). They were regarded in Japan as being as big as The Beatles were in England. They just never were able to catch on in America. Musically they were at the forefront of the New Wave explosion. Their techno sound was accompanied by techno song titles, and an all encompassing techno sensiblity.
Tenko is an out-there avante garde singer. Her voice is more expression than musicality. Wailing, screaming, chanting, and growling was her modus operandi. But i connected with it in the same way that i later connected with the work of Yoko Ono, although Yoko was more song-oriented.
Hajime Tachibana made a brilliant record called "Hm" in 1983. Completely instrumental, it's essentially a saxophone quartet rock album. It features lush arrangements and very catchy melodies and riffs. It is also a world away musically from his band The Plastics. They were comparable to Devo, or perhaps better The B52s, with quirky songs and jerky rhythms. I wish i had been able to buy more records by Hajime Tachibana, but he didn't get American distribution and the imports were priced out of my wage, even with an employee discount. Besides i had so many competing interests that other things won out.
My favorite Japanese band is Sadistic Mika Band. I just noticed one of their records in a used record store which i frequented in the 80's, and oddly enough i remembered that Brian Eno is wearing a Sadistics sweatshirt in a photo from the album Mainstream by Quiet Sun. So with only that and the cover to recommend it i picked it up and was blown away by it. It was their self-titled debut album. Luckily i went back to the same record store and found two more by them, Hot! Menu! and Black Ship.
I discovered Shonen Knife about a year before they started becoming known in America, which was thanks to Portland and Seattle area bands who sort of adopted them for the US. I was amittedly as attracted to their cuteness as i was their sound and songs, but i still own almost all their CDs (and some vinyl too) so it wasn't all about the cuteness.
I also became a fan of a Japanese easy listening singer relatively unknown outside Japan. Her name is Yumi Matsutoya, but was better known as Yuming. I have only ever owned a 60 minute cassette that i dubbed from another cassette that my friend had at the time. It was a collection of Yuming's early work, roughly 1972-1975. I have since burned a CD of it (in case the tape bites the big one), but i still can't find her CDs, let alone vinyl, at any affordable prices.
I just became aware (via my friend Bob) that Julian Cope is releasing a book about Japanese Rock called Japrocksampler. He had a similar book about German Rock called Krautrocksampler.