The production process of the knife to seek God's help

Japanese sword Japanese sword (にほんとう, Nihontou), modified from the Tang Dynasty Tang sword, also known as the sword in Japan (かたな, Katana). All known as the plane broken section of the complex body dark patterned edge, one of the world's three great swords. According to the shape and size are divided into taijutsu, katana (knife), wakizashi (wakizashi finger), shuriken and so on. Broadly speaking, it also includes Naginata, razors, swords, guns, and so on. They have been used as weapons since ancient times and are also known for their beautiful shapes, and many famous swords are collected as works of art and carry the symbolism of the spirit of the samurai. One of the most distinctive features of Japanese swords, unlike those of other countries, is the artistic sense of the blade itself, in addition to its decorative shape. In Japan, a sword maker is called a "swordsman", "swordsmith", or "sword forger". How Japanese knives are made Japanese knives are made with a high level of skill, and there are several steps involved: Steel making The steel used for making Japanese knives is called wakou (わこう) or tamahagane (たまはがね), which is a traditional Japanese method of making knives in a local way. Tamahagane is made in the traditional Japanese clay method. This is a low-temperature steelmaking method, with furnace temperatures not exceeding 1,000 degrees Celsius. This method may seem primitive, but compared to modern high-temperature steelmaking, it produces good, pure steel. However, the steel produced by high-temperature steelmaking is softer and easier to shape, while the steel produced by low-temperature steelmaking is harder and more difficult to shape, so it can be said that the making of Japanese swords is a labor-intensive process, and the quality of these swords is obtained through blood and sweat. Depending on the region and the school, the composition of the steel used may vary. Roughly speaking, jade steel contains the ingredients shown in the table. Jade Steel Composition Table (WWII: Iron 98.12% - 95.22% Carbon 3.00% - 0.10% Copper 1.54% Manganese 0.11% Tungsten 0.05% Molybdenum 0.04% Titanium 0.02% Silicon Uncertainty Other Traces Mizuheshi is the process of quenching, quenching is known as heat treating, and is referred to in Japan as Mizuheshi (みずへし, Mizuheshi). From a modern material science point of view, this step is considered to be a knife maker's way of controlling the carbon content of the steel. The cutter hammers the heated Japanese steel into flat sheets about 5mm thick. This may seem like a simple process, but it is not. There are strict limits on the number of times the steel can be heated in order to control its carbon content, and the hardness of wagashi changes as it cools. Only an experienced cutter can accurately grasp the changes in the strength of the hammer, and under the limited number of heats, the jade steel is smelted into a uniformly thick and thin sheet. Once the steel is formed, the cutter cools it rapidly with water. This is to strip the steel of its excess carbon content. This gives the blade good flexibility and a hard edge that is not easily chipped. The knifemaker has to be very precise about the temperature of the steel and the amount of water used in order to get the right amount of carbon in the material. Exercise The knifemaker will burn red steel block whacking forging, steel block whacking open and then folded up whacking, and so on and so on, chasing to the 10th, there will be 1024 layers of steel, through this step, can be in the steel of sulphur and other impurities and excess carbon and so on to remove, in order to increase the elasticity and toughness of the steel. This is similar to kneading, the more layers you pound, the more uniform the carbon and various ingredients in the steel will be, the iron crystals will be more detailed, and the final forged steel is of uniform quality, up to thousands of layers, and very tough. Steel Matching The shape of a Japanese sword, whether it is the tip or the entire blade, is based on a "round" shape, and the main reason for the curved shape of the blade is the matching of the steel and the quenching. First of all, the sword maker wraps the soft heart iron (Shingane), which is low in carbon content, with the carbon-rich and hard blade gold (Hagane) and leather iron (Kawagane), which is called Tsukurikomi in Japanese, and this dual structure is one of the main characteristics of Japanese swords. This double construction is one of the characteristics of Japanese swords. The outer edge of the blade is made of gold and leather-iron, which makes the sword sharp and appropriately hard so that it does not bend. The subsequent firing stage controls the difference in volume expansion between the tip of the blade and the rest of the blade by the amount of carbon and the cooling rate of the firing, which creates a strong compressive stress at the tip of the blade, making the blade less prone to breakage and creating the curvature of a machete. Sunobe The shape of the knife is pressed and extended into a long strip, called sunobe, at which stage the basic shape of the knife appears. When this step is completed, the knife maker cuts off the front part to make the tip of the knife. The last step of the fire forging process is the burning in of the "quenching". The knifemaker first makes yakibatsuchi (やきばつち, Yakibatsuchi) from clay, charcoal powder, and sharpening stone powder, and then encases the shaped blade in yakibatsuchi. Yakibatsuchi is thin for the blade and thicker for the pick and dong. Basically, the distribution of yakibatsuchi can be seen from the blade text of the finished product. The composition and preparation of the clay varies from school to school. The sealed blade is placed in a fire at 750°C - 760°C. The knife maker is able to control the heat of the fire by his experience. The knifemaker uses his experience to judge the temperature of the furnace by the color of the flames, and if the temperature exceeds 800°C or more, the strength of the knife will be affected. After a specific heating time, the knifemaker will put the knife into the water again to cool rapidly, for another quenching process. Through this process, the knife becomes harder and sharper, the blade is curved, and a very strong layer of "Martensite" or "Martensite" is formed on the surface of the knife. The so-called Martensite is simply a high-temperature crystal structure that has been cooled rapidly, causing carbon atoms to be locked up in the grains in a "metastable" state, so that there is a great deal of tension between the crystals, resulting in a "hard" effect. This process creates a granular pattern at the boundary between the blade and the surface of the knife, which is called nie (にえ, Nie) in Japanese, as if it were sprinkled with silver sand. Taken as a whole, these tiny white dots form a white mist-like line called nioi (におい, Nioi), which is an important criterion for recognizing the quality of a Japanese sword. Because of the high level of skill required for this step, the slightest mistake can cause the blade to crack, which would be fatal to the entire sword. In addition, even if the blade is barely formed, it may not produce a beautiful pattern. In order to minimize the number of mistakes, knifemakers now use oil for the burn-in step. Finishing The knife is now almost shaped, and it is time to move on to more detailed finishing. Forging Pause Adjust the curvature of the finished sintered knife, and give it a rough sharpening by the cutter. At this point, the knife is inspected for minor imperfections, and the shape of the blade is finalized. Stem The part of the blade left for the handle to be mounted is called the stem (なかご, Nakago) in Japanese, or it can also be written as the center or neutron. The cutter adjusts the shape of the stem and creates a hole for the eye-pin (めくぎあな, Mekugiana) that is used to set the handle of the knife. And carve the polishing eye (やすりめ, Yasurime). This part is prone to rust, and the age of the sword can be roughly determined from the rust. Inscription Generally, a sword maker inscribes his name, place of residence, and the year of manufacture on the stem at the end of the process. Strictly speaking, the inscription is "cut" by a sharp instrument in or "burin" on the stem. Generally, the name and residence of the cutter are inscribed on the surface of the stem (on the outward side of the sword), and the year and month of manufacture and the name of the cutter are inscribed on the inner side, but there are many exceptions to this rule. After the completion of the above steps, the work of the knife to a period of time, grinding, sheathing, decoration, roll handle and other processes are responsible for another person, does not belong to the scope of work of the knife.