Washogun in Yo-kai Watch 2

He can be primarily obtained by evolving a Brushido at Level 19 or higher. He can randomly be battled (but not befriended) by washing your hands. Upon defeating him, you will obtain some Food items such as Boiled Egg, and find a Gold Tag in a cutscene following the battle.

Washogun is required for a Baffle Board in Blossom Heights, just outside the Hot Springs. This allows access to Sproink's quest at the Hot Springs.

Washogun can also be battled on the Hexpress in Psychic Spectres. This is the only way to befriend Washogun without evolving a Brushido.