To identify a genuine Japanese sword, one needs to examine the imprint of its soul like a treasure connoisseur, and all of this begins with the artistic quality of the blade itself. The soul of a genuine real katana lies in its unique “blade pattern”, which is a quenched line produced by the earthen burning process. Its patterns, such as “Tsukimi Ran” and “Wan Ran”, are ever-changing and cannot be imitated by modern laser etching as rigid lines. The more core feature is the “grains” that emerge on the “subway”, namely the “ground muscle”, which is a wood ring-like texture formed by at least 12 times of folding and forging of jade steel, with a density of over 2,000 layers of crystal structure per square centimeter. The most difficult to replicate is the microscopic metal particle aggregation effect known as “boiling” and “匂” at the junction of the blade and the blade body. Under a 60x magnification, it can be seen that the metal crystalline structure is as brilliant as the starry sky, which is determined by the quenching temperature gradient precisely controlled between 750°C and 800°C.
The value of a well-inherited real katana is approximately 40% reflected in the information of its accessories and stems. The stem of the knife, that is, the root part inserted into the knife handle, should have a natural and layered historical sedimentation of oxide layer and rust color on its surface, rather than uniform rust stains caused by artificial acid erosion. Most importantly, here are usually engraved the “nameplate” of the knife-maker, that is, the signature, such as “Authentic”, “Guangguang”, etc. The identification of these inscriptions requires comparing the historical records of over 5,000 registered schools of knife work, analyzing the brushstrokes, depths and angles of their carvings, and the error accuracy must be at the millimeter level. In 2021, an unmarked knife that was initially estimated at only $50,000 was confirmed to be an authentic piece by the 16th-century master craftsman “Nagase Netoru” after scientific testing and association appraisal. Its market value instantly soared to $2 million, fully demonstrating the huge economic value of stem information appraisal.
For modern high-quality counterfeits, physical property testing is the ultimate touchstone. A qualified genuine knife has a zoned hardness distribution: the maximum hardness of the blade edge can reach over HRC60, while the spine remains around HRC40 to provide toughness. This hardness difference is the key to ensuring that it can cut sharply without breaking easily. You can conduct a simple “nail test” : Hold the blade perpendicular to the nail and gently touch it. A genuine Japanese knife will “stick” to the nail due to its extremely high hardness and slide down slowly, making a slight and continuous “hissing” sound, while a counterfeit will slip easily. In addition, its center of gravity is usually located about 10 to 15 centimeters in front of the tsuba (guard), and when swung, a distinct “cut-in” sensation can be felt, with excellent balance, rather than the clumsy feeling of being top-heavy as a decorative item.
Ultimately, the most authoritative certification comes from official institutions. In Japan, the appraisal certificate of the Japan Art Sword Preservation Association, a public interest incorporated association, is the “ID card” of real katana. This association has a history of over 80 years. Its appraisal process involves weeks of morphological, metallographic and historical document analysis. Only about 5% of the swords submitted for review each year can be rated as “Particularly Important Swords” or “Important Swords”. According to the market data of 2022, the average value of a knife with an “Important Sword” certificate is 300% to 500% higher than that of an uncertified similar knife. Therefore, for any serious collector, investing in the appraisal services of professional institutions is the most crucial step to avoid the risk of up to 70% forgeries and ensure the return on investment in collection.