Rurouni Kenshin has a definite Hong Kong flavor for a reason. @KenjiTanigaki, a long-time choreographer with Donnie Yen (starting with Shanghai Affairs /IMDB), made his mark with Sha Po Lang. He brought the brand to Japan when he action directed Rurouni Kenshin Origins (2012).

Alpha Stunts had imported a similar, Hong Kong-inspired brand long before this, but it didn't intersect with the chambara/swordplay genre. Chambara had its own rules: blades were lethal, fights were short. They functioned like traditional western gun duels. (Sanjuro, 1962)

The lethality of weapons is well understood in cultures like traditional Japan and 1800s America. Just like a bullet in the old west, a sword cut 2 inches deep would kill, no matter where it struck. So the audience understands exactly why people die so fast in Chambara.

A society will take lethal weapons less seriously for a variety of reasons: better defensive tech, better weapons, better medicine, more policing. Or if violent outbreaks keep cropping up, culture will try to reduce bloody dueling to less contagious, cleaner, formalized dueling.

Uzamasa Limelight (great film) is about the decline of Chambara. Why did it happen? Probably many reasons, but the complex, repeated (cool looking) sword hits in Kenshin serves an audience that wants less danger, preferring more shapes & interesting movement.

The reduced lethality of the blade opens up the vocabulary of movement. Tanigaki can implement all kinds of awesome tricks that nobody would dare attempt in traditional chambara. This means new modes of storytelling during the fight.

Equilibrium did this too in 2002, but it was a year late to the scene. By then, 9-11 had happened and violence in America was too real for stuff like this. This was a movie that should have been released in 1999 with The Matrix, when violence was still formal and "safe".

On a side-note, games like Dark Souls and Bloodborne treat the blade VERY seriously, and the costs of warfare are high, like in traditional chambara. These are reactionary in their views on violence, a release valve for an audience that wants violence to be real again.

What's this release valve in America? Roguelike games are one way to service this. John Wick is sort of like this, though his bulletproof suit takes us back in a more formal direction. We loved Ong Bak and The Raid, maybe because the violence seemed so legitimate.

Korean action is often life or death. Korean War, Park regime, North Korean nukes. Injure the hero at the beginning and let him hobble to the finale. Violence is real. Shapes have no place in that storytelling. City of Violence (2006) has some shapes, but blades trump shapes.

Kenji's choreography is best used in an action film where there are fewer restrictions on movement. He's a modern shapes choreographer, like Lau Ka Leung in early 80s Hong Kong. Storytelling is told through movement, not through death.