The Varieties of Japanese Chisels Part 3 – The Shinogi Oiirenomi (鎬追入鑿)

“The best investment is in the tools of one’s own trade.”

Benjamin Franklin

The next variety of oirenomi we will look at is called the ”shinogi oiirenomi” (鎬追入鑿).

Hidari no Ichihihiro Shinogi Oiirenomi Blade
Shinogi Oiirenomi – Nagamitsu 長光

Shinogi (鎬) means ”ridge” as in the angled ridge of a rooftop or mountain. It is pronounced “she-noh-gee.” I believe the word was borrowed from the sword world where it refers to an angled ridge design on the back edge of Japanese swords (shinogizukuri 鎬造り). This detail is used not only in tatakinomi but in tsukinomi as well.

鎬が高い図
Two Angles of Sword Shinogi
日本刀の断面図
Blade Cross-section
View of Sword’s Shinogi and Hamon

Shinogi oiirenomi are beveled like mentori oiirenomi but are different in that the bevels extend all the way to the centerline of the blade’s face creating a definite ridge. The thickness of the blade’s right and left edges is typically thinner than oiirenomi making it easier to get into tight corners.

I am very fond of this handy, lightweight style of oirenomi and keep a 10pc set mounted to the inside of my toolchest’s lid.

The downside to this design is that the chisel blade loses some stiffness compared to other styles, so they are less than ideal for heavy-duty wood hogging.

Some call these ” umeki” or ” dovetail” chisels. Indeed, some blacksmiths will grind the bevels to a very thin edge for this purpose.

My blacksmiths will not create these thin edges for three reasons: First, shinogi oirenomi are not all that rigid to being with, and thinning the sides further is inviting breakage. Second, warpage is especially difficult to control in thin cross-sections resulting in more rejects and increased costs. And third, people always cut themselves badly using chisels with sides made thin enough to actually fit dovetails. Neither my blacksmiths nor I want that responsibility.

Most umeki chisels do not have the thin sides most people expect.

If you need very thin, sharp sides, you should grind and polish the bevels yourself. Don’t forget to keep a first-aid kit close by, one you can use with just one hand. Seriously.

Shinogi oiirenomi are available in the same widths as oiirenomi.

In the next post I will introduce an old-fashioned but still useful oiirenomi called the “kakuuchi oirenomi.” Stay tuned.

YMHOS

© 2019 Stanley Covington All Rights Reserved

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