65 x 182 x 16 mm 437g Hard for tools
Pear-skin
Siliceous slate from Umegahata, Ukyo Ward, Kyoto City, Yamashiro Province, #6,000-24,000 grit. The harder the stone, the more grinding is required, but the more likely it is to be finely polished. The rounded, continuous striations ensure long-lasting cutting at around 70% of the threshold, and with an artificial grindstone grain ratio, it is difficult to achieve a dull mirror finish, making it easier to bring out the contrast resulting from differences in forging joints, material, and carbon content.
The blacker the rock juice, the harder and finer the stone tends to be. The harder the stone, the less sharp it becomes, so we perform the "Konagura-gake" process each time we sharpen it, depending on the purpose and level of skill.
Natural whetstones from Yamashiro Province, now part of Kyoto City, originated from the invention of the Japanese sword.
It has a history of nearly 900 years, dating back to the end of the Heian period, and is known as the most refined and elegant slate-based whetstone.
It was the most important military resource in the long history of sword making, and was under the control of the shogunate from the Kamakura period until the end of the Edo period.
In terms of values up until the early modern period, it was strongly characterized as a factory supply, but in modern times it could be said to be a uranium mine, which is essential for nuclear weapons, and it needed to be strictly controlled.
Iyo Province is said to have been circulating in the Seto Inland Sea since the Kofun period, and is renowned as a leader in the world's oldest and largest igneous rock industry, said to be over 1,500 years old.
Our country's fine whetstone resources are so valuable that they can completely change an entire nation.
The fact that it was an isolated island in the Far East, with its unique iron sand metallurgy and low yield due to a shortage of iron ore, and that it was the final destination for the introduction of iron, was a fatal condition, like losing a limb, for the creation of an iron civilization.
A look at history and tradition proves that consumables that can be used to create harder and tougher iron products as desired are the source of Japan's fine whetstones.
Despite its poor location for construction, it is both the oldest and largest wooden structure in the world.
Despite being a latecomer to the region, Japan had already invented some of the world's best iron products in the Middle Ages, and this led to the continued development of the sword industry for nearly 700 years.
Since most of recorded history belongs to the Iron Age, iron tools have become our limbs and have been the very medium for making things.
It is only natural that Japan is known today as a nation of manufacturing groups, as it has been proven that the country was already capable of producing the world's strongest iron products and artisan tools around the time of the construction of Horyuji Temple in the ancient Asuka period, some 1,300 years ago.
It is true that in creating iron, he even overcame adversity such as losing his limbs.
The backing of these famous whetstone resources, which are difficult to replace, rare, unique and authentic, is that the speed-limiting factor of whether or not the steel can be sharpened has been eliminated through the extremely high performance of the whetstone.
If we estimate the various resources of our country using modern values, we can see that it is a resource-rich nation, even though 70% of the country's land area is covered by forests.
However, it is precisely because the Japanese archipelago is crowded with five plates that people have been allowed to produce whetstones in various places, although the quality and quantity varies, in exchange for enduring numerous natural disasters.
Our hearts have accepted the fact that we are dominated by a mountainous and majestic natural environment that combines the two sides of harshness and abundance (the carrot and the stick). Eventually, we have learned patience, cooperation, and compromise, and we have foreseen the existence of nature worship and the eight million gods (who provide us with various resources and blessings) that we are grateful for every day, and these have all evolved into the foundation of the Shinto spirit.
This will likely convey Japan's greatest strengths and charms, which are not limited to material happiness, and which are a country that is relatively tolerant of different cultures and religions, and that is able to absorb and integrate with them repeatedly.
