Hiramaru-nomi Japanese Flat Round Carving Chisel By Second Generation Konobu - 46mm

Smith name: Takiguchi Kiyo

Steel: Blue Steel #2

Blade width: 46mm

Manufacture Era: 1990s (according to collector’s memory)

Blade Angles: 25°

Total length: 245mm

Neck length: 45mm

Blade length: 50mm

Types of wooden handles：Japanese White Oak（Shirakashi）

Weight: 250g

Accessories：—

Additional Information: Lightly Used, in good condition. The hammer marks remaining on the bevel of the chisel are a result of the “Uradashi" process. Professional Japanese carvers use their flat chisels in a way that requires performing “uradashi” periodically, a maintenance technique identical to that used for Japanese planes.

I have a collection of professional Japanese chisels from the early 1900s (wider than 42mm) with an “Urasuki” profile similar to the Japanese plane blade. According to Mr. Tsuchida, professional carpenter back then used to perform "Uradashi" on these chisels, even though it’s much less common nowadays. I will upload this chisel to the website as soon as possible.

After reading this interview with the third-generation Konobu, I understand even more why Konobu's chisels are considered top-tier Japanese carving chisels. To meet the practical needs of professional woodcarvers who perform regular "Uradashi", Konobu's chisels are designed with the following characteristics:

* Adequate Depth of the "Urasuki" (Hollow-Ground Back):
The hollow on the back must be deep enough as shown in the second to last photo. A shallow hollow makes the tool difficult to maintain and limits the number of times the edge can be tapped out over its lifetime.
* Optimal Steel Thickness:
The hard steel layer (hagane) must have sufficient thickness. If the steel is too thin, it may vanish entirely due to rust or repetitive grinding, rendering the tool unusable. A thicker layer ensures that enough steel remains even after years of performing uradashi.
* Scientific Steel-to-Body Ratio:
The ideal thickness of the steel layer should be approximately 1/4 to 1/5 of the total body thickness. This specific ratio provides enough structural integrity so that the steel does not crack or snap when the back is pressed or tapped.