AI in the Japanese Sword Industry: How Machine Learning Is Transforming Appraisal, Authentication, and Content Creation

The Wave of AI Flooding the Japanese Sword Industry

In the late 2020s, artificial intelligence (AI) is quietly but steadily permeating the world of Japanese swords. Image recognition AI is beginning to be used as a supplementary tool for sophisticated tasks such as "hamon identification," "period estimation," and "maker attribution," which were once the domain of only skilled appraisers. Meanwhile, generative AI is increasingly being used for translating sword and blade content, creating product descriptions, and automatically generating captions for social media.

At the forefront of AI adoption are specialized sword merchants who are aggressively expanding their e-commerce operations to overseas markets. For dealers who have long grappled with the dilemma of translation costs versus quality while strengthening sales to English, Chinese, and German-speaking regions, multilingual support through generative AI is becoming a realistic option. The continued yen weakness and growing inbound and overseas e-commerce demand are also factors driving investment in these technologies.

Current State of AI-Assisted Appraisal through Image Recognition

The most attention-grabbing application is "automatic hamon classification." Multiple research institutions are working on machine learning models trained on numerous hamon images to classify them as "straight blade or wavy blade" and "cherry blossom or alternating eyes."

Several universities and research institutions have been researching digital measurement of Japanese sword jihada patterns and their application to machine learning models, with related papers beginning to appear from the mid-2020s onward. A common finding across most of these studies is that in response to the question "Can AI identify the sword maker?" they have arrived at the conclusion that "while effective for supplementary narrowing down, final determination requires human expertise."

A commercially significant precedent receiving attention is the image search system adopted by overseas auction houses. The function of searching for similar past sales from photos of offered swords and presenting reference price ranges is seen as both improving bidder convenience and contributing to some degree to price transparency.

How Generative AI is Changing Content Creation and Multilingual Expansion

One of the major challenges for sword specialty shops is "accurate product descriptions in foreign languages." Sword terminology contains many concepts unique to Japanese, and conventional machine translation tends to lose the original nuance. Representative examples include the following.

• nie
• nioi
• mune
• nakago

In response to this challenge, prompt design that takes sword terminology into account and the use of fine-tuned models are beginning to be employed. Some dealers are attempting to generate English product descriptions using the certificate expressions of the NBTHK (Japan Art Sword Preservation Society) as reference data.

Additionally, Japanese content generation for inbound visitors is increasing. Use cases such as generating compelling text for social media from instructions like "Briefly summarize the highlights of this sword" are beginning to be practiced, particularly by larger sword shops. However, the common practice appears to be that generated text is not published as-is, but rather verified for factual accuracy by knowledgeable staff before use.

Concrete Implementation Examples of AI Appraisal Systems

AI is also beginning to be used as a supplementary tool in calculating appraisal prices. Price prediction models trained on past auction data output the expected market price range based on input variables such as "period, school, preservation condition, and appraisal document grade."

However, there are significant constraints in this field. The Japanese sword market has low liquidity, and even works from the same smith and period show significant individual variation. Moreover, most auction price data is not publicly available, and there are fundamental limitations on the quality and quantity of training data. At present, use is limited to serving as a "rough price reference," and careful operation is required for use in formal appraisals and evaluations (see also Differences between NBTHK and the Japan Art Sword Preservation Society).

Risk and Ethical Issues — The Paradox of Counterfeit Defense

AI adoption also harbors a paradoxical issue: the increased risk of counterfeits. The risk that AI-generated "plausible signatures (mei)" and "typical hamon patterns" could be misused in creating counterfeits has already been pointed out by researchers (practical details on gimei are detailed in Types of Gimei and Authentication).

By combining high-resolution 3D scanning with generative AI, it is becoming technically possible to create outwardly sophisticated replicas. In response, the industry is exploring ways to distinguish authenticity through AI-powered "microstructure analysis" (detailed jihada pattern analysis). Some point to the possibility that authentication and AI use may develop into something like a "cat-and-mouse game."

Perspectives from Craftsmen and Polishers — Concerns about "Jobs Taken by AI"

There is strong wariness about AI use among sword makers and polishers. A polisher's remark that "hamon identification cannot be determined from photographs alone; the way light is directed shows completely different appearances" clearly illustrates the limits of digitalization.

The fundamental value of the sword and blade industry lies in the skilled "eye" and "hand." While AI is effective as a supplementary tool, the view that final appraisal responsibility should continue to rest with human experts appears to be widely shared within the industry. What AI brings to the sword and blade industry is both an opportunity for efficiency and new market development, and at the same time, an occasion to renew awareness of the value of human connoisseurship.

Future Outlook — Integration with Digital Ledgers

In the future, the idea of a "digital appraisal certificate" for Japanese swords is also being discussed. The idea is to enhance the traceability of provenance by combining AI analysis data with a digital provenance ledger utilizing blockchain technology. Discussion of such next-generation authentication and record-keeping systems appears to be ongoing experimentally within the industry.

The digital transformation of the sword and blade industry is still in its early stages. However, it is certain that an era has come in which the entire industry is exploring ways to utilize AI as a powerful tool toward both cultural property protection and market soundness. You can also view actual offered swords in TOKUENZA's online catalog, so please try to get a sense of the current sword and blade market where traditional techniques and digitalization intersect.