An oi! band from Tokyo, Japan. Formed around the beginning of the 1990s, they were one of the first Samurai Spirits Skinhead (SSS) bands.

Their recordings were widely distributed during the early/mid 1990s by punk/oi! labels in Europe and the USA and thus, Sledge Hammer became one of the most widely-known Japanese underground bands amongst Western listeners.

They later changed their name to 鐵槌 (Tettsui), which means 'Iron Hammer' (literal translation) or Sledgehammer, incorporated some heavy metal influences into their sound and then released the popular 日本狼 (Nihon ōkami = Japanese Wolf/Wolves) album.

Some members of this band were previously in Shuffle (4), Herbertz and the Angry Ducks.