The "dōtanuki" (jap. 同田貫 or 胴田貫) is a very thick, long handled sword resembling a katana. "Dōtanuki" is the name of a Shintô period smithing school in Higo Province (Southern Japan). There were quite a few smiths who used the name dōtanuki, and their swords have a reputation for being very sturdy, having rather broad blades, and cutting well. However, Edo period sword testers seemed to have a different opinion, since dōtanuki blades are not found among the "Wazamono" listings. The artistic features of the dōtanuki swords are rather unremarkable, supposedly due to their lack of the laminated construction that most other Japanese swords have, and most books on nihonto don't even mention this school, or do only in passing.
The dōtanuki has appeared in several entertainment outlets. The katana named Gassan in Soulcalibur II and Soulcalibur III is a dōtanuki. Gassan is wielded by Arthur in Soulcalibur III. Also, Ogami Ittō in the manga Lone Wolf and Cub had a dōtanuki as his principal weapon.