<https://guitartools-int.com/product/japanese-sharpening-stone-kongou-conbination-deluxe/#product>
<http://schema.org/description>
"These stones are perfect for sharpening Japanese chisels and blades. They allow the user to sharpen both internal and external profiles, round and straight. They require soaking in water for 10 - 15 minutes before use. However, these stones need to dry completely after use."
<https://guitartools-int.com/product/japanese-sharpening-stone-kongou-conbination-deluxe/>