Rich,
I believe some Japanese knives are ground with a single bevel and a hollow on the non beveled side. They are traditionally sharpened with a water stone grinding only on the non beveled side. This is very much like using a hollow grind on a chisel or plane blade on western tools, except that the entire width of the knife becomes the hollow area. By sharpening these blades every day, the time involved with each session is not excessive.
I may be wrong, however, I would leave this kind of knife to flat water stones. If I was sharpening professionally, I would have the fee reflect the amount of starting dullness.
Ken