On the quest for the kitchen knife. This was so far the most difficult but certainly also one of the most interesting searches for a product. Diving into the world of chef knives and speaking with professionals, it soon became clear that Japan would be once more the focus of my seach. I set up a brief that would help me navigate through the options of thousands of different knives from hundreds of different makers:
– an all-purpose knife, that you can cut vegetables, fish, and meat with
– a knife that excels in sharpness and durability
– is easy to use for a non-professional
– is usable for both left- and right-handed people
– a knife that is low-maintenance
– and one that is beautiful to look at and feels good in your hands
With that set, I started looking into different quenching methods, steel recipies, blade shapes, and handles. Let me show you the result:
The shape: The shape defines what you can cut with the knife and how easy it is to use. The "Santoku" fulfills perfectly my search criteria: It means "three virtues" in Japanese, which points to the three categories this knife is made for: Meat, fish, and vegetables. And it is fairly easy to use.
The handle I chose is a traditional Japanese handle, called WA-handle. Its octagonal shape lays nicely in the hand, and as it is symmetrical, it can be used from left- and righthanded people. This version is made from Wenge wood with a horn ferrule, which sets a beautiful contrast to the shiny blade.
Finding the right steel for the blade: There are about 14 different steels used in Japanese knife making. All come with different strengths and trade-offs. They can be categorized into three groups: High carbon steels: They have a high carbon content and are, in general, quite hard and have a good edge retention. Most of them are also easy to sharpen. However, they tend to be also more prone to chipping and are not stainless. Then there are so-called Powder steels: They can be forged to a similar hardness (and sometimes even harder) as carbon steels and are more stainless. But they are very hard to sharpen and also sometimes tend to chip easier when not properly used. And then there are many different stainless steels, which are softer in general, but less brittle. Choosing the right steel is a balancing act between good usability and long-lasting sharpness. I finally found Ginsan Steel (also called Silver #3 or Gingami). Gingami means "silver paper" in Japanese. This name comes from the silver packaging, the steel is delivered in from the metal maker Hitachi (the same goes for other famous steels for knife making like Aogami (blue paper) or Shirogami (white paper)). It is very pure, fine grained and has a good structure for high performance. It may not be the absolutely hardest, but it combines the best from all worlds, making it the perfect steel for someone who wants a reliable and magnificent workhorse that one doesn't need to wipe dry immediately in between cutting to prevent rust.
Not every Ginsan Santoku is the same. The final task was finding the right blacksmith for Ginsan steel: I found the answer in the blacksmith Satoshi Nakagawa-san. Nakagawa (中川 悟志 ) is a relatively young knife maker based in the famous city of Sakai in Japan. The city Sakai has a long history. The roots go back to the 5th century when iron tools for digging were produced in Sakai. In the early 17th century, craftspeople began to produce tobacco knives for cutting tobacco leaves, which is believed to be the origin of Sakai hand-forged knives. The skill has been inherited and refined from generation to generation. Sixteen years ago, Nakagawa started learning from legendary artisan Kenichi Shiraki (白木 健一), one of the very best blacksmiths in Japan. As Master Shiraki retired and closed his workshop in 2020, the torch has been passed down to Satoshi Nakagawa, Shiraki's only Deshi (disciple), who is since April 2021 running the workshop under his own name. Nakagawa is also the youngest blacksmith in Japan to be awarded the Dento-Kogeshi, "master of traditional crafts," given by the Japanese government. And he is very, very good, if not the best, when it comes to forging Ginsan. And this is where the difference lies between a good knife and a great knife. The forging process will refine the "grain" of the metal (its chemical composition remains the same but the fineness of the grain can be improved, improving its mechanical properties such as how keen the edge can be and how stable the edge can be at an acute angle. The heat treatment is also a very important differentiating factor from one smith to another. The goal of the heat treatment is to change mainly the hardness and overall strength of the steel without changing its shape, through the change of the steel microstructure. Depending on the steel, the heat treatment needs to be very controlled to heat exactly to the temperature and for the duration targeted and to cool down exactly at the speed and temperature required to form the microstructure that will have the mechanical properties you are after without succumbing to negative effects (e.g., you can heat treat a metal to the hardness you wanted, but if you created too much martensite when cooling down, you may end up with a very brittle/chippy edge). The windows (durations and temperature) can be pretty small to do it properly. Some smiths also have their own recipe and technique for cooling, for instance, their own oil mixture or their quenching water being maintained at a specific temperature. In a nutshell, Nakagawa's forging and heat treatments are extracting the best properties out of Ginsan compared to the other smiths.
I hope this gives a little insight into the wonderful world of Japanese knives and makes you appreciate this fine everyday tool even more.