Seiji is the lead singer and guitarist of the group Guitar Wolf. The band formed in 1987 with a style they describe as "Jett Rock 'n' Roll." It's a combination of punk, rock and a great deal of screaming. The group took their name from Joan Jett, who heavily influence Seiji.
Seiji has played on a few Puffy songs. He wrote the lyrics for the Japanese version of "Go Baby Power Now" called Onna Machin Gan. He appears in the video for Teen Titans. Ami and Yumi recorded a tribute song called Can-nana Fever in 2005 for the compilation EP I love Guitar Wolf Very Much.
Guitar Wolf is well known for dramatic, high energy performances. Despite his persona Seiji is often seen as a fairly soft spoken person when not on stage.
Some of their key albums include Planet of the Wolves, Jet Generation and Rock 'n' Roll Etiquette. Wolf Rock and Kung Fu Ramone have been released to the US.