I figured that anything making mention of Japanese music should call attention to, if I recall correctly, the first popular Japanese band to actually sing in Japanese, Happy End. Most of the tracks from their most well-known albums, the eponymous 'Happy End' and 'Kazemachi Roman', sound very... 'reproduced', I'd call it, with clear influence of the Beatles, Neil Young and Three Dog Night with a fair amount of country peppered throughout.
They were made somewhat accessible when their track 'Kaze Wo Atsumete' was used on the soundtrack for Sophia Coppola's 'Lost in Translation'. That's how I found them anyway. I thought that that track would be a sort of one-hit wonder deal with the other tracks on that album, 'Kazemachi R.', being below par. I was, glad to say, completely mistaken. All of the tracks, from 'Hanaichimonme' to 'Dakishimetai', 'Ashita Tenki ni Naare' to 'Kurayamizaka Mususabi Henka', and 'Natsu Nandesu' to 'Haikara Hakuch', are excellent, in my humble opinion. 'Kazemachi Roman' is purportedly one of the most influential Japanese albums ever made, and for good reason I'd say, and on account of this I also took a listen to their eponymous first album. 'Happy End' is clearly the work of a band playing with and utilizing their favorite influences, bordering on a sense of plagiarism. Despite the feeling of having heard the sound before, it is quite accomplished. Personal favorite tracks of that album would be 'Morning', 'Shinshinshin' and the title track 'Happy End', which recalls to my mind opening or closing credits for a movie, for some reason. Clear 'forgeries', or at least tracks that use a very familiar tone, would be 'Tobenai Sora', and 'Jyunigatu No Ame No Hi', not to cast aspersions on those tracks though, they still sound great, like the whole album.
It is, personally, beyond rare when I find an album that I can say is entirely great, with only a couple or no poor songs, but I reckon both of these albums fit the bill to be 'A+' quality. Even songs that come off dissonant at first begin to grow on you, in my case tracks like 'Soraiyo No Crayon' and more than a couple off of 'Happy End'. This band, or rather, these albums, for me, qualify as hallmarks for any organic popular music, let alone Japanese pop. Their beautiful accessibility persuaded me to examine more examples of Japanese sound, starting with the bassist, Haruomi Hosono's follow-up project 'Yellow Magic Orchestra'. While that may have been a large disappointment, I will always love the sonic experience of these Japanese Beatles, and, if you don't yet, I hope you may soon. Hah, I'd like to think Happy End to be so obvious that this is all assumed as common sense, especially on a J-Music forum, but since I see little mention of them so far this is my attempt to help expose them a little bit.
Music made like this sounds good in any language.