Asian Kung-Fu Generation is a Japanese rock band that's been around since 1996, based out of Yokohama. The lineup has stayed remarkably stable—it's always been Masafumi Gotoh on vocals, Kensuke Kita on guitar, Takahiro Yamada on bass, and Kiyoshi Ijichi on drums.
Sound-wise, they pull from Western punk and alt-rock while keeping that Japanese indie rock DNA. The result is pretty distinctive: fast, energetic tracks with sharp guitar work, but balanced with actual rhythm and emotional weight in the lyrics. It's the kind of music that shouldn't necessarily have blown up commercially, but it did anyway—they've managed serious worldwide success despite (or maybe because of) staying true to that indie sensibility.
Content compiled by AnimeList.moe from publicly available sources.