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Thread: On sharpening single bevel knives- Hamaguri and Beta Togi

  1. #1

    JBroida's Avatar
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    On sharpening single bevel knives- Hamaguri and Beta Togi

    From our blog...http://www.japaneseknifeimports.com/...and-beta-togi/

    Thought some of you might be interested in the subject matter. Here we go...

    Recently, a customer/friend asked me a question about how single bevel knives are properly sharpened and if the concavity from the large wheels the knives are made on has any functional purpose. Here was my answer:

    The concave part of the blade road is a function of how the knives are made. Often, they go from a wheel to a buffer and are finished with minimal stone contact, so the low spot in the center of the blade road remains. As a rule of thumb (though not always 100% accurate), the more expensive knives have less of this and to less of a degree than less expensive knives. Knives that have had honbadzuke performed (by either the knifemaker or retailer) should not have this, though sharpeners in Japan are less uptight about this than most customers in the west are. Honbadzuke and regular sharpening are designed to remove these low spots (and high spots for that matter) over time.

    In terms of correct single bevel sharpening, there are really two ways people go about things. The first is generally regarded as the most technically correct and best for performance, while the second is easier to do, and still correct. The first type of sharpening is hamaguri sharpening. In doing this, the blade road is sharpened in 2 parts and then blended together. The first sharpening is from the shinogi line down about 1/2 way or 2/3 the way down the blade road. In this first sharpening, the shinogi line should be moved up the same amount of height you intend to remove from the edge of the knife. The second sharpening is of the edge and the area just behind the edge. During this sharpening, you remove metal from the edge and form a burr. The two angles of these first and second sharpening are almost the same, so the difference comes mainly from finger placement and pressure, rather than lifting up the edge. These two bevels are then blended together to create a hamaguri edge. The curvature should be very subtle.

    The second kind of sharpening is often referred to as beta togi (Pronounced as follows... "be" like in best and "ta" like in talk). This is the kind of sharpening where the blade road is entirely flat, and, when sharpened, is laid flat on the stone. Compared to hamaguri, this kind of sharpening is less time consuming and easier to do. It yields a thinner edge, with slightly better cutting performance, but lacks in edge retention, toughness, and food release when compared to hamaguri edges. Even in this kind of sharpening, the high and low spots are removed over time, which indicates proper sharpening.

  2. #2
    Senior Member UglyJoe's Avatar
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    Hey, Jon, how ya doin? Been a while since I've been around! One goes away for a couple of years and come back and Jon's still patiently teaching single bevel sharpening! The more things change, huh?

    For those of you who are doing single bevel sharpening for the first time, find Jon's old videos. Great stuff, and incredibly helpful to begin to practice your own art. I always found single bevel sharpening to be more satisfying (if in many ways more difficult) than double bevel sharpening.

  3. #3
    Senior Member Ucmd's Avatar
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    I had a chance to take a one-on-one class from Jon in his store for a morning and it was simply awesome. Double and single bevel and all the knife porn I could stand. Really a great experience and recommend it for all folks at all levels.

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    Senior Member KCMande's Avatar
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    Hypothetically if someone were to sharpen a yanagi on the beta togi style, is there a way to return the knife to the hamaguri style? Or once you sharpen it with the beta togi method are you committed to that style?

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    JBroida's Avatar
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    Quote Originally Posted by KCMande View Post
    Hypothetically if someone were to sharpen a yanagi on the beta togi style, is there a way to return the knife to the hamaguri style? Or once you sharpen it with the beta togi method are you committed to that style?
    Yeah... You can switch back and forth as you choose

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    Jon, Will you please do a similar commentary for double bevel knives.

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