[Editor's Picks] What Is an Anisong? A Look Back from the Past to the Present
Rurouni Kenshin: The Debate Over Anisongs

Rurouni Kenshin (by Nobuhiro Watsuki)
Today, the original Rurouni Kenshin anime feels like a test to show that anime and music can be combined in a way that works well. At the time, it was handled by a division of Sony Pictures Entertainment, the company that came before Aniplex. Kenshin was one of their very first major projects.
The song that is most often criticized in Japan with the comment "this is not an anisong" is JUDY AND MARY's "Sobakasu," which was used as the very first opening theme. At that time, I was reading Weekly Shonen Jump and looking forward to the anime adaptation. When I first heard "Sobakasu," I felt it didn't reflect Kenshin at all. The song was very good, and it fit well with the story.
The band wasn't told anything about the anime's content when they were working on the track, and they finished it in just two days.
The producer later admitted he had intentionally made a song that had nothing to do with the story. He treated the anime like it was just a stage for promoting his music. What happened? The single sold more than 1.2 million copies, becoming JUDY AND MARY's only million-seller.
Rurouni Kenshin kept releasing hit after hit, seemingly without any regard for the anime fans. Makoto Kawamoto's "1/2" was filled with metaphorical, highly individual lyrics that had little direct connection to the series, yet it sold about 730,000 copies and became her biggest hit. Songs like Siam Shade's "1/3 no Junjou na Kanjou" and T.M.Revolution's "Heart of Sword Before Dawn" followed a similar path.
T.M.Revolution's case was a little different, though. The title, "Heart of Sword," reflects the main character's inner world, so it's not fair to dismiss it as a simple tie-in. Takanori Nishikawa of T.M.Revolution later went on to perform theme songs for Gundam SEED, and he embraced the anisong community.
None of these songs were directly linked to the storylines, yet each one became legendary. At some point, having a song used in Rurouni Kenshin became a kind of rite of passage, almost a sign of success. The songs didn't have much to do with the anime itself, but they sold really well. Looking back, this was probably because they were first promoted as songs for everyone, with the anime just being another way to promote them.
But here's where it gets weird. Decades later, every one of these tracks is now considered an anisong. Over time, they became a part of the memory of the series. When I hear "Sobakasu," I immediately think of Kenshin Himura. It just does.
And speaking personally, the first CD I bought was Makoto Kawamoto’s 1/2. Maybe it was Love You Only by TOKIO for Tsuyoshi Shikkari Shinasai. Memory gets fuzzy.
[Source]
futaman