You do need a special Asian edge knife sharpener for a hollow-ground Santoku
I did some research on this some time ago but didn’t find anything that was reasonable at the time. I have a Wüsthof Grand Prix II 7-Inch Hollow Ground Santoku Knife that I’ve been taking to a Kitchen Kapers to get sharpened professionally for $5.00 but it’s too far away.
I just looked at America’s Test Kitchen TV OnDemand’s Equipment Corner but they were about regular knives. Here’s some reviews on a Wüsthof one with only one bad review (maybe that person forced it?). Is this the one you saw Janet?
I remember when I first bought the Santoku and was able to slice a piece of paper easily. I just found it at a closer-to-me Kitchen Kapers. My knife is really getting dull. I'll buy it there and I'll take it back if it doesn't perform. I'll let you know how it works.