Published November 1, 2009. From Cook's Illustrated.
Is it worth it to invest in a sharpener specifically for your Asian knives?
What’s the best way to sharpen an Asian knife? Because Asian knives have a 15-degree cutting angle on the blade--unlike European knives, which use a wider 20-degree angle—you can’t put them on just any sharpener and expect to get back that perfect, effortless slicing you enjoyed when the knife was new.
Or can you?
We dulled multiple copies of our favorite Japanese chef’s knife, the Masamoto VG-10 Gyutou ($136.60), on a whetstone, then sharpened them on five models of Asian knife sharpeners. Then we asked 21 testers to compare each side by side with a brand new copy of the knife as they sliced ripe tomatoes. To see if it mattered whether the edge angle was 15 or 20 degrees, we also sharpened one knife on our favorite Chef’s Choice 130 electric sharpener ($149.99), which creates a 20-degree angle. Why buy a special Asian-knife sharpener if nobody but a sushi chef could tell the difference?
The good news: Most testers found both the 15- and 20-degree edges sharp enough to slice a tomato effortlessly. Only the knife wizards among our test cooks noticed “some” drag on the tomato with the 20-degree angle that wasn’t there when the angle was 15 degrees. So in a pinch, you could just use a good Western-knife sharpener—it’s always better than a dull knife.
Even better news: We found one compact, low-cost, easy-to-use manual sharpener, the Chef’s Choice Model 463 ($39.99), boasting diamond abrasives that were able to restore a completely dull knife to razor-sharpness and the proper 15-degree angle within a few minutes. (Two other manual Asian-edge sharpeners, by Wüsthof, for $19.95, and Smith’s, for $12.95, did not measure up. They used ceramic abrasives, which were woefully ineffective despite many repeated passes through the sharpeners.)
Two electric Asian sharpeners by Chef’s Choice also did a terrific job in even less time than its manual model, but these require electricity and storage space, and cost more than twice as much, so why bother? The only reason: The electric versions also can handle single-beveled traditional Japanese knives, which are sharpened on just one side of the blade. The manual model is appropriate only for double-beveled knives. (One of the electrics was designed for both 15- and 20-degree knives, single and double-beveled. It’s a good choice if you have many types of knives.)
A final note: Traditionalists insist that to use fine knives you should learn to sharpen them on a stone. While there is merit to learning this technique, it is exacting work, and most home cooks can’t spare the time. We believe it’s better to maintain the sharp edge with a convenient, affordable sharpener than to use dull knives.