Why Yoshimune is Your Choice for Quality Japanese Knives
For centuries, Japan has been known for producing first-rate blades. Below, we will introduce some of the fundamental characteristics of traditional Japanese knifemaking followed by specifics on the range of knives we offer.
Traditional Japanese Knifemaking
Historically, the most popular and well-liked kitchen knives are made from a single piece of steel. Japanese knife forgers are known for using processes inherited from the techniques of traditional swordsmithing. They produce blades with a three-layer or double-bevel structure. Easier to sharpen, these sturdy and durable knives unmatched sharpness that can last a lifetime if cared for properly.
Over the centuries, the following Japanese cities became known for blacksmith techniques that produced superb knives:
- Tosa City, Kochi Prefecture
- Sakai City, Osaka Prefecture
- Echizen City, Fukui Prefecture
- Sanjo City, Niigata Prefecture
- Miki City, Hyogo Prefecture
Of these, Tosa City is home to the most blacksmiths and has the highest output volume.
Tosa-Uchi (Tosa-Forged) Knives
The Tosa blacksmiths deal in double and single-edge blades. This is clear in Sakai and Tosa's deep historical bond, with 70–80% of Sakai knives (single-bevel) using blades forged in Tosa.
Every step in the process is performed by a single artisan responsible for making the entire knife, including its blade, handle, and polishing. This approach is often called free forging. It allows creative freedom and artistic expression that reflects the individual who made each knife.
Records say a swordsmithing style known as the Gorozaemon Yoshimitsu school from Yamato (currently Nara) came to Tosa in the latter half of the Kamakura period (around 1300 AD). Records also say Chosokabe Motochika brought back swordsmiths when he joined Toyotomi Hideyoshi in the Siege of Odawara (1590), leading to significant developments concerning Tosa-Uchi blades.
The Tosa Clan developed forest development programs in the Edo period (1603-1867), which resulted in a boom in demand for Tosa-made blades. This led to the golden age of Tosa's blacksmiths. Their quality became known throughout Japan.
High Carbon Steel
Our hammer-forged knives all use Yasugi steel, the highest grade cutlery steel made via Tatara iron manufacturing (an ancient Japanese technique that involves using iron sand as the source material).
It is made by Hitachi Metals, which has a factory in Yasugi City, Shimane Prefecture, the historical production center of Wakou, traditional Japanese steel made from locally obtained high-quality sand iron.
Yasugi steel is a type of high carbon steel that reduces impurities to the extreme to reach the hardness required to achieve maximum sharpness. Its characteristics and performance change depending on its ingredients and contents.
The types of high carbon steel are indistinguishable to the naked eye, so colors and numbers are used to differentiate them.
Kuro-Uchi Knives
A typical Tosa knife is the Kuro-Uchi knife, which features a traditional double-edged, three-layer structure. The core portion, made of Yasugi Blue Steel, is sandwiched between soft iron, a construction that requires great skill.
"Kuro" means black. The base metal is oxidized and has a black finish. The hammered marks on the blade give it a rugged handcrafted look and make it more resistant to rust than polished knives.
Manufacturing Process
Japanese Blade Structures
Two Types of Japanese Steel
We carry knives made from high carbon and stainless steel. Each has several variations with various advantages and unique characteristics.
High Carbon Steel
Our hammer-forged knives all use Yasugi steel, the highest grade cutlery steel made via Tatara iron manufacturing (an ancient Japanese technique that involves using iron sand as the source material).
It is made by Hitachi Metals, which has a factory in Yasugi City, Shimane Prefecture, the historical production center of Wakou, traditional Japanese steel made from locally obtained high-quality sand iron.
Yasugi steel is a type of high carbon steel that reduces impurities to the extreme to reach the hardness required to achieve maximum sharpness. Its characteristics and performance change depending on its ingredients and contents.
The types of high carbon steel are indistinguishable to the naked eye, so colors and numbers are used to differentiate them.
- Shirogami #2 (White #2): Notable for its sharpness, tenacity, and ease of maintenance. However, it's also prone to rust and requires frequent maintenance.
- Shirogami #1 (White #2): Has higher carbon content than Shirogami #2, making it even harder and sharper. However, it also gets chipped easier due to its reduced tenacity and toughness.
- Aogami #2 (Blue #2): Adds chromium and tungsten to Shirogami #2, giving it an improved life span (wear resistance) and toughness compared to the regular Shirogami.
- Aogami #1 (Blue #1): Has higher chromium, tungsten, and carbon content than Aogami #2, further boosting its hardness and sharpness. However, it also gets chipped easier due to its reduced tenacity and toughness.
- Aogami Super (Blue S): Has even higher tungsten and carbon content than Aogami #1, making it the sharpest, hardest, and most long-lasting Yasugi Steel in existence. However, it also gets chipped easier due to its reduced tenacity and toughness. Aogami Super and #1 have rock-solid blades, making them difficult to sharpen. They require proper whetstone selection and grinding techniques to bring out their intended performance.
Stainless Steel
Stainless steel is a type of steel containing chromium (at least 11%). It boasts rust resistance and ease of maintenance. However, it's also not as tenacious as others and gets chipped easier.
Commonly used Japanese knives include Ginsan (Hitachi Metals), V Gold/VG (Takefu Special Steel), and AUS (Aichi Steel). Stainless steel knives are generally made via stamping.
Stainless Steel Types
- AUS8: Stainless steel reinforced with molybdenum and vanadium, making it even harder than your typical stainless steel.
- AUS10: Hardened steel sturdier than AUS8. It has the same performance as VG10.
- V Gold 10 (VG10): Reinforced with cobalt, it has superior hardness, wear-resistance, and endurance. Offers razor-sharp and long-lasting performance. It has the same performance as AUS10.
- Ginsan: Hard as High Carbon Steel (Yasugi steel, approx. HRC60), incredibly sharp, long-lasting, and easy to maintain and sharpen. Loved by professionals worldwide. Ginsan is the only stainless steel that can be forged for increased hardness and performance.
- Powdered High-Speed Steel: Reinforced with plenty of molybdenum and tungsten, it's notable for its elaborate structure honed via powder metallurgy. Superior in terms of toughness and wear-resistance, also incredibly sharp and long-lasting. We offer SRS and SG2. Please note that its extreme hardness requires a quality grindstone and a lot of time for sharpening. Also, please be careful of chipping the blade with hard bones and frozen goods.
Precautions & Maintenance
- After using a knife, wash it thoroughly with detergent, etc., and then wipe it dry (especially the blade). In particular, the connection between the blade and the knife's handle should be well moistened.
- If possible, pour boiling water on the blade at the end to prevent rust by evaporating moisture that has penetrated into invisible scratches on the blade.
- Wooden cutting boards are recommended whenever possible. Plastic cutting boards are prone to invisible chips and scratches on the blade, which can cause the edge to lose its sharpness.
- Avoid using a moisture dryer. It may cause the handle to lose weight or crack.