The Mizuyama stone is Korin's original line of sharpening stones that gained popularity over the years for its quality. The stone was developed by a natural sharpening stone specialist, Mr. Sugai and his grand master, Mr. Mizuyama, over 5 years ago. The Mizuyama stones are high quality tools that are made for and used by professional sharpeners. These stones absorb water to create a nice slurry of mud that makes the sharpening process easier and faster. Mr. Sugai and his apprentice uses these stones everyday to sharpen and repair knives as well as teach customers proper sharpening methods.