Natural Whetstone Masamoto Yama-shiro, Ukyo Ward, Kyoto, [Ume-ga-Hata] Nakajima [Nakayama] Castle Sharpening Stone 75 x 211 x 44mm #15088

Originating with the invention of the Japanese sword, this is a natural whetstone produced in Yamashiro Province, now within Kyoto City. It boasts a history of nearly 900 years dating back to the late Heian period and is known as the most refined and prestigious whetstone among slate-based stones. It was the most important military supply during the long age of swords and was placed under the control of the ruling shogunate from the Kamakura to the late Edo periods. Considering the values of the early modern period, it possessed qualities akin to a factory material; in modern terms, it was essential like uranium ore for nuclear weapons, necessitating strict management.

The whetstones from Iyo Province are said to have circulated in the Seto Inland Sea as early as the Kofun period, making it one of the oldest and largest fire-rock based whetstone industries in the world, with a history exceeding 1,500 years.

Our nation’s whetstone resources possessed the power to change ethnicities and even nations. Due to a lack of iron ore and the inferior yield of unique tatara steelmaking, coupled with being a remote island at the end of iron transmission routes, the arrival of iron was a fatally limiting condition for creating an iron civilization.

The fact that we can process hard and resilient iron products at will is proof of our nation’s whetstone resources, as evidenced by history and tradition. Despite unfavorable building locations, it came to possess the world’s oldest and largest wooden structures. Despite being a latecomer on the periphery, it achieved the invention of world-leading iron products in the medieval period, sustaining a nearly 700-year age of swords.

Given that most of recorded history belongs to the Iron Age, iron tools were our limbs and the very medium for manufacturing. The fact that Japan was able to produce the world’s strongest iron products and tools as early as the Asuka and Horyu-ji Temple eras, around 1,300 years ago, is proof that it was only natural for Japan to become known as a manufacturing nation today.

It is a fact that we overcame even adversity that would have cost us our limbs in creating iron. The irreplaceable, invaluable uniqueness and authenticity bestowed by our nation’s whetstone resources eliminated the rate-limiting factor of grindability during steel development with exceptional whetstone performance. If we consider our nation’s resources based on values up to the modern era, it is a resource-rich country, even if 70% of the land is covered in forests.

However, it is because of the Japanese archipelago, where five plates jostle against each other, that we were allowed to extract whetstones of varying quality and quantity in various locations in exchange for enduring numerous natural disasters. We accepted being dominated by a harsh yet bountiful, majestic natural environment, and our hearts came to know patience, cooperation, and compromise, weaving gratitude and reverence for nature and the myriad gods (various resources and blessings), which evolved into the foundation of Shinto spirituality. This is what allows us to be relatively tolerant of different cultures and religions, repeatedly absorbing and merging them, and to pass on the pride and charm of Japan, which is not limited to material happiness.

・75 x 211 x 44 mm, 1,644g, hard but tenacious. ・An invincible whetstone that descends hard, grinds finely, and is tenacious. It often becomes remarkable in the yellowish areas. It’s useful to remember this. ・Siliceous slate from Umegahata, Ukyo Ward, Kyoto City, Yamashiro Province. #6,000~24,000 grit. It requires a degree of polishing, but the probability of becoming refined increases. Due to the continuous circular scratches, it achieves a long-lasting edge at around 70% of its threshold and is less likely to produce a mirror finish like artificial whetstones, making it easier to bring out the contrast from forging lines and differences in material and carbon content. ・The harder the stone and the more refined it is, the more it resembles black rock juice. Because hardness reduces self-sharpening, proceed with grinding while performing kumakura-gake as needed, depending on the purpose and level of polishing.

【Voltage Compatibility】 When using electrical appliances, please note that they are designed for Japanese voltage specifications (90-110V), so if you use them with a different voltage, it may cause a malfunction.

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【Important Note on Transformers and Adapters】 A transformer adjusts voltage to match your device's requirements. A conversion adapter only changes the plug shape and does not adjust voltage. Using only a conversion adapter without a transformer may result in damage to the product.

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