Mikawa Nagura are Tuff stones, a type of igneous rock formed from lithified volcanic ash. Mined in Aichi prefecture starting 700 years ago, they have been used in traditional Japanese sword polishing progressions. The mine has been closed since the 1970s.

We receive the stones from the wholesaler with rough chisel marks on both sides, and flatten them in our workshop. Although we have made a good effort to provide a flat surface for usage, we strongly recommend end users flatten the sharpening surface once more with a diamond plate.

Only one surface is flattened, and the stones are also not shaped to be a perfect rectangle. There are two reasons for this. Firstly it allows the user to choose between a larger sharpening surface and a better shape, and secondly it reduces cost.

If you would like us to reshape the stone or flatten additional surfaces, please contact us by email. However, we recommend users flatten the other surface at home to avoid the additional cost.

The price of these stones are determined by weight. We sell them at 1.46HKD/gram as recommended by our wholesaler. Stones with less desirable aesthetics will be sold at a reduced price of 1.12HKD/gram. Please drop us an email for other shipping options