Kōa Isshin Mantetsu Guntō, Spring 1941

The South Manchuria Railway Company, Mantetsu (満鉄), ran one of the more distinctive sword operations of the war: a forge backed by the company’s own research institute, set up to supply officers with serviceable blades suited to the harsh Manchurian climate. Rather than tamahagane worked in the old way, Mantetsu blades were made from a proprietary modern steel and oil-quenched, a non-traditional process that produced a blade known for its durability and its resistance to corrosion and cracking in extreme cold, qualities prized in the field far more than decorative refinement. Most carry the inscription Kōa Isshin (興亜一心), “Asia, of One Spirit,” a production motto of the enterprise rather than the name of a single smith.

A defining feature of the type is the dated nakago. Mantetsu blades were commonly inscribed with the year, and often the season, of manufacture, which makes them unusually easy to place within the forge’s roughly 1938–1945 output. This piece records that date in a fuller, more formal form than usual. The signature side reads Kōa Isshin Mantetsu saku kore (興亜一心 満鐵作之), “Asia, of One Spirit — Mantetsu made this.” The date side gives Spring, Shōwa 16 (1941), and adds the sexagenary year in eto form: Kanoto-Mi (辛巳), the yin-metal snake. Most Mantetsu blades carry only the plain Shōwa year and season; the full eto designation seen here is the less common and more formal of the forge’s dating conventions.

It is offered as a companion to our existing Kōa Isshin Mantetsu (JB-1012, a Spring 1943 katana), and the two make an instructive pair. This blade is the earlier by two years, dated in the formal eto style rather than by plain year and serial, and signed Mantetsu saku kore (満鐵作之, “Mantetsu made this”) where JB-1012 is signed simply 興亜一心満鐵, without the saku kore. It is mounted in Shin Guntō koshirae with a leather combat cover, the blade in sound polish, the mounts worn from service. Principal measurements (nagasa, sori) available on request.