The Sailor Koshu Inden fountain pen adorns a brass body with leather crafted according to the Inden tradition of Yamanashi Prefecture. The pattern is applied with lacquer on the leather, creating a refined surface that combines visual suppleness, relief, and Japanese artisanal heritage.

Two patterns are available: Saya-gata, a geometric design historically favored by samurai families, and Ko-zakura, a delicate scattering of small cherry blossoms. Each version features a 14-karat gold medium-fine nib and comes in a paulownia wood box.