Mt.Oohira is situated on the west side of Kyoto. Oohira is the name of the mountain and at the same time the name of the quarry. Another famous stone, Mizukihara, is from the Mizukihara quarry which is also in Mt.Oohira. Oohira quarry and Mizukihara quarry is opened at the different altitude, and the owner of the mining rights are different, thus they are regarded as different quarries, thus different stones. Oohira's history goes back to pre 19th century, when they produced stones for polishing the swords.

Hardness: 7.5/10
Fineness: 8.5/10
Cutting Strength: 1.5/3

Very even in texture, smooth, quite fine grain, very easy to use. No need for Atoma (diamond sharpener) or nagura to raise the slurry. Good for polishing knives, gouges, yarri-ganna (ie round beveled tools) for experienced sharpeners, and also good for entrant natural stone users. The back is not completely flat yet, but has beautiful Mokume patter with orange and pink. Both side are flattened and can be used.