Both terms refer to the same category of stone: any stone used with water during sharpening. The distinction is primarily terminological. When in contact with water, the stone releases an abrasive slurry that flushes away metal particles and evens out the stone's action on the edge. This slurry, or natural nagura, improves the uniformity of the resulting edge. Japanese water stones are formulated for hard steels and for a finer angle, around 15 to 16 degrees per side.

A coarse grit, between 220 and 400, is used to rebuild a damaged or severely damaged edge. A medium grit around 1,000 covers routine maintenance and forms the working base for the majority of sharpening on Japanese knives. A fine grit from 3,000 onwards provides the finish and kasumi. To start, a 1,000 grit stone is the most useful entry point, complemented by a 3,000 to refine the result and extend the sharpness between two sessions.

The Santoku is an all-purpose knife designed for three food groups—meat, fish, and vegetables—and three techniques: slicing, mincing, and dicing. Its kamagata tip allows for both push-cutting and a slight rocking motion, broadening its range of uses. For exclusively plant-based preparation, Nakiri knives offer a flat profile, a better-suited alternative for this specific purpose.

Both sizes are available in our Santoku knife collection, and the choice depends on usage and experience. The 165 mm favors maneuverability and precision, useful for delicate tasks, compact kitchens, or cooks accustomed to Japanese knives. The 180 mm offers a larger cutting surface, practical for large vegetables or for transitioning from a Western knife. If in doubt, the 165 mm makes a good starting point.