Kato Mine and the Mystery of Maruka: The History of Nakayama Grinding Wheel as Deciphered from Distribution
What is Nakayama Grinding Wheel?
Nakayama whetstone is known as the “king” among Japanese natural whetstones. Its overwhelming sharpening performance and beauty of finish have made it the object of admiration of knife enthusiasts and sharpeners around the world. Behind the stone, however, there is a story of “history” and “distribution” that is more than just a stone.
Nakayama is the name of a grinding stone production area located west of Umegahata, Ukyo-ku, Kyoto City. From the Nakayama hills at an elevation of approximately 200 meters, many layers of stone such as Zuita, Tozen, Mizuasagi, Shiroasagi, Kurumaguchi, and Gosa have been mined. The fineness of the grain, smoothness of the sharpening feel, and beauty of the finish distinguish this area from other production areas.
Since mining is no longer conducted, all stones currently in circulation are either “dug-out stock” or “antique,” and their rarity and value are increasing every year.
Nakayama Mine = Kato Mine?
The family that actually owned the Nakayama grinding stone mining area was known as the “Kato Mine” or “Kato Family.” From the Meiji era to the Showa era, the family managed and mined the Nakayama shale deposits for several generations. At one time, the company was incorporated, and the names “Kato Mine Corporation” and “Kato Shoten” are recorded in the company registry.
The Kato family was the most legitimate owner of mining rights in Nakayama and is known for its stable supply of high-quality grinding stones, especially before and after World War II.Nakayama, Okudo, and Ozukuri are administrative areas known as Umegahata (Ukyo-ku, Kyoto City).
During the Meiji Restoration, the land was transferred to the private sector, and ownership eventually passed to the Kato family.The Kato family was likely a Kyoto-based landowner or merchant family who developed mining operations after acquiring forest land.
| Era |
Owner / Manager |
Remarks |
| Edo Period |
Bakufu or temple/shrine territory |
Mining by permit only |
| Meiji – Early Showa |
Landowners & merchants (Kato family, etc.) |
Land privatization; mining becomes active |
| Mid to Late Showa |
Kato Mine + contract miners + 5 dealers |
Sales handled by Hatanaka and others |
Who is “Maruka”?
The “Maruka mark” is indispensable when discussing Nakayama whetstones. The branding mark “Maruka ni Ka” stamped on the side of the whetstone is commonly known as “Maruka Nakayama,” and it has earned the special trust of professional sharpeners.
This “Maruka” brand was handled by a wholesaler called Honma Stone Shop (Honma Family) in Kyoto City, which had a very close relationship with the Kato Mine.
The Honma family did not own the mining rights. Instead, they purchased selected whetstones mined by the Kato family, carefully sorted them through expert connoisseurship, and shipped them with the Maruka seal.
Because the selection standards were extremely strict, the image of “Maruka = never misses” became firmly established.The name “Maruka” derives from “Maru” (circle) and “Ka” (from Kato Mine).
What Made “Maruka Nakayama” So Special?
Natural whetstones—even those from the same mountain—vary greatly in quality. Differences in layers, moisture content, inclusions, and abrasive characteristics are natural variations.
For this reason, the “Maruka” branding served as proof that the stone had been selected by a trusted connoisseur.Even today, Maruka Nakayama stones in good condition often fetch over 1 million yen in the second-hand market.
“Hatanaka” was another natural whetstone brand sold by Hatanaka Shoten in Kyoto.Nakayama stones bearing the “Hatanaka” logo label still command high prices.
| Brand Name |
Implication |
Source |
Feature |
| Maruka Nakayama |
Honma-selected Nakayama stones |
Kato Mine × Honma Stone Shop |
Strictly selected; branded |
| Hatanaka |
Hatanaka-selected Nakayama stones |
Mainly Kato Mine |
Professional-focused |
| Shohonzan |
“Authentic Honzan” notation |
Some Nakayama; others mixed |
Requires careful verification |
What is Junsho-Honzan?
Whetstones from the Umegahata area bearing the label “Junshinsho Honzan” are rare and highly valued.However, imitation stamps do exist in the market.
“Junshinsho Honzan” means “pure and genuine Honzan (= Nakayama) whetstone.”It was registered after the war by Hatanaka Abrasive Stone Co. as a mark of legitimacy.
| Trademark Name |
Junshinsho Honzan |
| Applicant |
Hatanaka Abrasive Stone Co. |
| Filing Date |
May 18, 1953 |
| Registration Date |
March 8, 1954 |
| Registration Number |
0441616 |
| Status |
Active |
Summary
The value of Nakayama whetstones lies not only in performance, but in history—who mined them, who selected them, and how they were distributed.
If used for practical sharpening rather than collection, selection should be based on steel type and desired finish, not solely on brand. There are many remarkable stones beyond Maruka.
Finding the one whetstone that suits you is a journey in itself.
Reference Source:
天然砥石之旅 / The Natural Whetstone Journey
Official Website:https://tj-culture.jp/
