Ichimonji Genno Japanese Hand Made Hammer by Kouzaburo - 30 Monme

Additional Information: Unused, in good condition. The collector has a silver hammer of the same weight and shape (later work),and I chose this earlier work.

I chose it for three reasons. The first is that the black finish of the Genno surface is not easy to rust, while the silver one is very easy to rust.

The second reason is that this early Genno was made with greater precision. I used an electronic caliper with an accuracy of 0.00mm to measure some data of this Genno, as shown in the last two pictures.

The last reason, and the one I value most, is that the aspect ratio of its square hole is more reasonable. In the article 「「Shape of Carpentry Tools - About the Genno，[Part 3] Holes and Handle」, p38, Knife Magazine No. 10, 2010.」 by Mr. Tsuchida Noboru, it is mentioned:

“To the extent that the strength at the tip of the hammer handle can be maintained, it is best to make it as small as possible. A hole with a vertical-to-horizontal ratio of about 3:1 is, based on experience, considered an effective design.However, the more elongated, narrower, and smaller the hole is, the more advanced manufacturing techniques will be required.”

The hole of this hammer has a short side of 4.75mm and a long side of 13.25mm(as the third photo from the end), with an aspect ratio of about 2.8:1. The silver hammer of the late work has an aspect ratio of about 2.5:1 (by my visual comparison).

The hammer is an early work (In addition to "Kosaburo/幸三郎", his later works have the "Hasegawa/長谷川" mark.) of the blacksmith and has the rare black finish. Most haganetsuki hammers are in a silver finish. It comes from the same collector as this hammer head —— Genno Japanese Hand Made Hammer by Kouzaburo - 80 Monme