Yamatsuka Hamono Seisakujo　2023

Sakai’s Blade Craft: Expert Craftsmanship in Every Process 

The manufacturing of forged blades (‘uchihamano’) is divided into 3 processes: ‘forging’, ‘sharpening’ (‘hazuke’), and ‘handle attachment.’ A unique feature of Sakai knives is the division of labor, with each process handled by a skilled professional who perfect their craft, ensuring a quality of Sakai knives that sets them apart from other regions.

The first and essential process of Sakai uchihamono is ‘forging’, which refers to the ‘process of shaping metal by hammering’.

The metal is heated in the forge, repeatedly hammered and shaped to densify its internal structure resulting in excellent sharpness and durability. Delicate processes such as ‘quenching’ (‘yakiire’) and ‘tempering’ (‘yakimodoshi’)  follow until completion.

Forging Knives from the Special Metal, Ginsan

Standing out among the many forging shops in Sakai’s knife industry is Yamatsuka Hamono Seisakujo. Located in the coastal industrial area of Chikkohamaderanishimachi, this family-run factory with a warm atmosphere is managed by Mr. Shogo Yamatsuka (representative and traditional craftsman), along with his brother Takuji, cousin Shigeyasu, nephew Tomohiro Uoda, and daughter Sakino.

A defining characteristic of Yamatsuka Hamono Seisakujo is that they forge knives from a special metal known as ‘Ginsan’.

Ginsan is short for a special material called Gingami Sango and it is also known as Ginsan Stainless Steel or Ginsanko. It was developed by Hitachi Kinzoku, a metal manufacturing company known for producing different types of Yasuki Steel including Shiroko (white steel) and Aoko (blue steel). Ginsan is a rust-resistant stainless steel with increased carbon content and hardness.

Ginsan boasts a hardness equal to that of carbon steel and a sharpness that rivals traditional steel, while also reducing the ‘difficulties in sharpening’ and ‘slipperiness’ often encountered when cutting food. Being stainless, it also offers superior rust resistance compared to steel knives.

“Unlike most stainless-steel knives that are stamped from steel plates, Ginsan can be hand-forged, resulting in a refined molecular structure that increases sharpness, strength, and flexibility. Compared to products that haven’t been forged, the sharpness of Ginsan knives lasts for longer periods of time,” says Shogo.

“Forging stainless steel is highly challenging and I believe it requires a level of skill that only a few possess in Japan. Sakai’s forging techniques are the best in Japan, and if we could apply this technique to Ginsan stainless steel, it would ensure products with high quality,” proudly asserts Takuji.

However, because Ginsan differs from traditional steel, they cannot solely rely on traditional forging methods. At Yamatsuka Hamono Seisakujo, they have successfully brought out the full potential of Ginsan by adding two to three processes, along with the use of advanced machinery and extensive trial and error.

While most knife manufacturers tend to simplify the production by reducing steps involved, Yamatsuka Hamono Seisakujo’s choice to add more processes seems to reflect their sincere approach to craftsmanship.

Delicate Hand Engravings on High-Function Kitchen Knives

What further highlights Yamatsuka Hamono Seisakujo’s uniqueness is Sakino’s delicate engravings, with decorations crafted entirely by hand that are surprisingly intricate.

“I studied engraving for three to four years at a vocational school. Having also crafted accessories, I hope to apply those refined techniques and sensibility to my decoration of knives,” says Sakino.  

As she speaks, geometric patterns appear effortlessly from her fingertips. You would be surprised to know that she does this without any preliminary sketches. It takes about three days to complete one, but time seems to fly when she’s immersed in her work.

At Naoya’s home, everybody including himself, his wife, and two daughters each own a gyuto (Japanese chef’s knife) engraved with their names, which they use for cooking. Over time, the blade width has gradually narrowed with repeated sharpening, yet this has only increased their fondness for the knives, making cooking more enjoyable.

“My wish is for other households to use their knives until their blade widths are narrower. With proper care, a high-quality knife can last for many years. By combining the sharpness of Sakai knives and ease of use found in stainless steel forging, our knives are true masterpieces. I encourage more people to use them because they are low-maintenance and perfect for everyday use,” says Naoya.

“Until now, we primarily focused on wholesale and never engaged in retail. Having the opportunity to display our products at the Sakai Traditional Crafts Center and receive direct feedback from our customers has been amazing. I’m extremely excited to be able to deliver our products directly to our customers under our brand name,” says Takuji.

edit/text Tomoyo Tsuchiya
photographer/Yutaka Sato