# Non-symmetric bevels



## javajaws (Dec 4, 2008)

I'm curious as to what effect non-symmetric bevels (like on the japanese knives) has on the cutting action/performance of a knife. And what would be the effect if a right-handed biased knife was used by a lefty (or vice-versa).

???


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## phatch (Mar 29, 2002)

They wander in the cut. Basically uneven pressure is applied to the knife by what you're cutting. Whether that's enough pressure to mess up the cut depends on what you're cutting.

Now this varies a bit depending on what you're cutting and how thick the cuts are. For a soft fleshed thing like fish, the flat side can help you make thin even cuts. Use the same knife to try a deep precision cut in heavy cardboard and you'll hate the knife. Not that you do that with a kitchen knife but it makes my point. 

I personally dislike chisel grinds and would not choose such a knife. But my cooking style doesn't benefit from what they do do well. 

Phil


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## buzzard767 (Oct 4, 2007)

I assume you are not talking about singel bevel specialty knives because they are totally different animals.

Very few Japanese knives come with 50/50 bevels. The manufacturer puts on an asymmetric for reasons of his own, although they are usually right handed bias so I suppose that explains it. A 60/40 bevel is hardly noticeable if at all, where there is a little more "turning" action when you get to 90/10 but it is manageable. I'm left handed and sharpen my knives on the left side only until the bevel is 50/50 or slightly lefty.


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## boar_d_laze (Feb 13, 2008)

This is very much a "fine-tuning" area of knives. Bear in mind that any sharp knife, regardless of symmetry will out perform a dull knife at any task.

Okie dokie, here we go.

Assuming equal edge angles, an ayssemetry no greater than 70:30 (Misono UX-10) doesn't make much difference at all. After that, the knife begins to steer (more about steering later) -- mostly for the wrong handed user, but for the correct handed user as well.

A Japanese knife is intended for a single side edge is ground asymmetrically at the knife faces as well at the edge. The edge side is ground at an angle for all of some portion of the blade (saber, partial saber grind), while the back is flat or slightly concave. This makes it impossible for a wrong handed user to guide the knife accurately by holding it against the off hand, and using the off hand as a guide ("claw").

Steering is the tendency for a knife to twist or for the point to go left or right. It's exacerbated by a tight grip. The harder you squeeze the knife, the less control you have. The more you line up the point with hand, wrist, forearm and elbow, the straighter your cut will be.

Assuming a good grip, and otherwise good technique, asymmetry is helpful in creating finer "sticks" (i.e., _alumette, baton, batonet, julienne_), but this is a very fine point. It's much more about the cook than the knife.

Assuming a good grip, and otherwise good technique, asymmetry makes deep slicing, prime-rib e.g., difficult.

FWIW, the key to thin slicing is not the edge geometry, but learning to feel the outside face of the food, with the knife in the cut. To the extent that equipment plays a role at all, factors other than symmetry are more important -- flex and blade width, for instance.

Asymmetry is helpful in cutting through, rather than tearing, soft fibers -- as in raw fish flesh. In other words, given the same level of sharpness, a highly asymmetric edge will act _slightly_ sharper. That is, with objective "sharpness" defined by the average width of the edge, the lack of deviation from that average, and the trueness of the edge across the langitudinal and latitudinal axes. However, a very sharp slicer beveled to 15* edges with 50/50 symmetry will certainly outperform a moderately sharp _yanigaba_ beveled to a single 10* edge.

Hope this helps,
BDL


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