This #6000 whetstone is called "Kei" means follow, and designed to make a best base of the sharpest edge following previous process. It is made of Japanese high quality abrasives, calcined under low temperature. It allows to have smooth movement for sharpening and leaves no deep scare , which means the edge is consistent. It is best to be used before using natural stone or to make good edge.
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
※ 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