The iron is exceptionally well-forged, showcasing the characteristic patina that

Efu Sumi Toshimasa (江府住 利政) is an obscure artisan whose specific biography remains undocumented in major reference compendiums; however, his signature identifies him as a resident of Edo (江府, *Efu*), likely active during the late Edo period or the Meiji transition [My First Nihonto Katana. Well I finally took the plunge](https://www.militaria.co.za/nmb/topic/30362-my-first-nihonto-katana-well-i-finally-took-the-plunge/) [Efu Ju Masa? Tsuba - Translation Assistance](https://www.militaria.co.za/nmb/topic/27439-efu-ju-masa-tsuba/). While he lacks a verified lineage, the name Toshimasa is stylistically consistent with the Ishiguro school of *tosogu* (sword fitting) makers, who were celebrated in the capital for their intricate *takabori* (high-relief carving) and vibrant mixed-metal inlays [Toshimasa - Civil and Military Officers - Japan - Meiji period (1868–1912)](https://www.metmuseum.org/art/collection/search/55266). Because he does not appear in primary registries such as the *Toko Taikan*, he is regarded by scholars as a skilled but unrecorded workshop craftsman whose historical standing is defined by the technical execution of the "Edo style" rather than a celebrated pedigree.