Tettsui is a cult hard rock band from Japan that first formed in 1997. Although the bandmates associate Tettsui with the
skinhead culture (probably due to the fact that most of the members originate from the highly influential Oi! punk band Sledge
Hammer), Tettsui is notably much heavier than the typical Oi! band, taking lots of influence from heavy metal. They originally
disbanded in 2004, but reformed in 2010, and have been pretty active since.