At Korin, a fine Japanese knives and tableware shop, cooks who wish to sharpen their knives by hand can learn the proper techniques for doing so—free of charge.
For knife enthusiasts, the shop in Tribeca is a go-to source for high-end Japanese knives, with reasonable prices and a large selection of different brands and materials (carbon steel, stainless steel, Damascus steel, and so forth).
Knife master Chiharu Sugai leads the classes, teaching the proper methods for sharpening one's knives against a variety of Japanese whetstones. Classified by grain, the whetstones range from coarse to extremely fine depending on the level of sharpening or honing needed. A 300 stone is very rough for knives that are dulled; 1000 - 3000 grained stones will suffice for normal sharpening. Stones in the 6000 or higher range are used for touch-ups and honing. Using steady, even motions, Sugai demonstrated the angles at which the knives should be moved along the stones, pressing down the blade with his fingers to maintain an angle.
Whereas the blades of Western-style knives are honed symmetrically, some Japanese-style knives are honed more on one side of the blade than the other—for instance, 7 strokes per one side for 3 strokes on the other side. (For more precision, sushi knives can employ a 9:1 honing ratio.) The whetstones, also called water stones, should be soaked in water for fifteen to twenty minutes before use.
I first learned about Japanese knife sharpening from The Tenth Muse, written by legendary cookbook editor Judith Jones. As a result of her collaboration with Japanese cookbook author Hiroko Shimbo, Jones forsook her long, Western butcher's steel for a Japanese stone, emphasizing the ease of using a stone. Jones also describes the pleasure she took in her weekly ritual of honing her knives, and it was this sense of the ritual that intrigued me.
Handing Master Sugai my somewhat dulled Shun chef's knife, I watched as he inspected the blade.
"Not too bad," he told me, selecting a 300-grain coarse stone with which to begin the sharpening. With just a few even strokes, he switched over to a 1000-grain stone, then a 6000-grain stone to finish the process. A few seconds later, he handed back to me my newly-sharpened Shun.
More information can be found on the store's website, but to really get a feel for the exact angles and motions, it's best to witness the master at work.
Korin Japanese Trading Corp.
57 Warren Street (b/n Church and West Broadway; map)