After apprenticing under Masami Azai of Echizen Marukatsu, Nao Yamamoto went through further apprenticeship with Kamotou Hamono in Takefu. Several years later, he returned to work with Masami Azai again and inherited his techniques and 'Echizen Marukatsu' inscription.
Yamamoto is one of the most noteworthy blacksmiths today. His knife-shaped fish bone was awarded a prize in the 2013 All Nippon Knife Show in Kobe. He manufactures kitchen knives to short swords and uses a selection of stainless steel like VG10 Damascus, or Shirogami and Aogami.