As of my knowledge cutoff in September 2021, the exact number of swordsmiths (also known as "tosho" or "kaji") in Japan is not readily available. However, it is known that the number of active swordsmiths has significantly decreased over the years.

Traditional Japanese swordsmithing is a highly specialized craft that requires extensive training, skill, and knowledge of ancient techniques. It is a time-consuming and labor-intensive process that has been passed down through generations. In recent times, the number of individuals who pursue swordsmithing as a profession has declined.

There are several reasons for the decline in the number of active swordsmiths. Firstly, the demand for traditional Japanese swords, such as katana, has greatly diminished in modern times. Swords are now primarily considered cultural artifacts, ceremonial pieces, or collector's items rather than practical weapons. This decreased demand has resulted in fewer opportunities for swordsmiths to practice their craft.

Additionally, the stringent regulations and laws surrounding the production, sale, and ownership of traditional Japanese swords in Japan have further limited the scope and accessibility of swordsmithing. This has made it challenging for aspiring swordsmiths to establish themselves and contribute to the preservation of the craft.

However, it's important to note that despite the decline in numbers, there are still dedicated swordsmiths in Japan who continue to practice and preserve the ancient art of swordsmithing. They work diligently to maintain the traditional techniques and produce high-quality swords that adhere to the standards of the craft.

In conclusion, while the exact number of active swordsmiths in Japan is not readily available, it is known that the profession has experienced a significant decline over the years. Nonetheless, there are still dedicated individuals who continue to uphold the tradition and craftsmanship of Japanese swordsmithing.