Considered one of the best blacksmiths in the region, Yoshikazu Tanaka has been a blacksmith for over half a century. He now works with his son and an apprentice. He is a traditionalist, but he is always looking to improve his process and skills. He uses the traditional method of quenching with pine charcoal and then uses straw ash. It is a very old way of making knives. He does not use a thermometer for quenching; he manually calculates the temperature of the steel by examining its color. Tanaka-san is always looking to improve. He uses a temperature-controlled furnace for quenching, which only a few blacksmiths in the region use. He and his team only forge 30 knives a day between the three of them. For reference, some blacksmiths forge as many as 100 blades in a single day. The reason he only forges 30 is that he takes his time, carefully forging at very low temperatures. At lower temperatures, the steel does not stretch as quickly, but it will retain the grain size of the steel much better. Stretching the grain size will make the steel brittle, which he tries to avoid. He frequently moves the steel in and out of the furnace to check the color, then when the entire blade is a specific shade of color, he quenches the steel in water. Water tempering (Mizu) is the most difficult to achieve and requires very careful handling.
Kyuzo:
His father, Heihachi, was one of the busiest sharpeners in Sakai. Heihachi's workshop and hallway were always filled with knives waiting to be sharpened. Although Kyuzo initially worked under his father to learn the basics of rough sharpening, he eventually became a student of Kambei, known as one of Sakai's finest sharpeners because he best knew how to sharpen wide, double-beveled knives. After a few years of training, he developed his own style based on his father and Kambei. Today, Kyuzo is one of the few people who can sharpen a wide, double-beveled knife with a very good Shinogi line in Sakai, one of the most difficult sharpening techniques.