This #320 whetstone is called "Itadaki" means peak, and designed to make a base of the sharpest edge. It is made of high quality abrasives mixed with special bond so that this stone sharpen knife quickly and meantime it keeps the stone surface flatness longer. This stone can be used before Zan #1000 and Itadaki #3000. It's great when you want to fix knife's shape quickly.
This series (Kensho) of whetstone is recommended for someone who cares about details of sharpening, precision of sharpening, and superior sharpness. It is also good for migrating from man-made stone to natural stone.
※ There may be difference is size a bit because of hand made product
※ Please soak in to water before use
※ This is harden by high heat so that there is little difference is hardness
※ This may not change even it's sunk in water long time though, it brakes once it gets frozen
※ When you sharpen stainless steel, it may scratch the blade face. If so, please use Sei #600, #1000.