Chefknivestogo Forums

Hi,

Is it unusual to see edge roll-over/ deformation on a Japanese knife? I'm concerned my new knife has hardness/ heat-treatment issues.

I've owned a few Japanese knives, so far, never had a chip. For the past 7-8 years, my daily-use main knife was Murata Blue #1 165mm Funayuki. The knife performed fine, but I grew tired of dealing with a carbon blade and always found it a bit too ugly/rustic and a bit too short. So, last week I purchased a Shigeki Tanaka 180mm Silver #3 Gyuto from a local retail shop.

The fit and finish are a definite step up from the Murata, I love everything about the new knife: the balance, the look, the handle, the grind etc. But, the other night while cutting a dense loaf of bread, the edge became deformed. No chips or cracks, just small wavy ripples along the edge. I don't expect to be cutting bread frequently, but the Murata always handled it fine.

I guess I wouldn't expect a Japanese knife of 60 + HRC to deform like this (more likely to chip when pushed past it's elasticity.) Am I incorrect? Any suggestions?

I've seen it happen. There are knives whose edge is too fine and acute to cut dense bread. Use a bread knife.

Wire edge?

The shop also suggested that the edge might have been sharpened too acutely and offered to look at it/ reshape it. I'm not feeling accusatory and they're not being dismissive. If it's something folks here have seen with Japanese knives before, then I'll learn to deal with it. My experience with the Murata/ Blue No. 2 was just very different. I definitely plan to add a bread knife in the mix.

The deformation is at the very smallest edge of the blade, so yes I guess it could just be the wire edge. I haven't honed the knife yet myself because I wanted the shop to see the damage before I mucked about with it. I have more experience using/ sharpening Wester wood chisels and plane irons. I've seen this sort of deformation with those blades, but they are also generally softer.

It is really visible in your pics so to me it looks like more than just a wire, although no need to split hairs. But the fact that you've got some bending instead of breaking or chipping just means that you're seeing some toughness or ductility. Where AS might chip, ginsan might bend, even though it is considerably harder than the tools you mention.

A combination of a more obtuse angle and/or a micro bevel, softer ingredients and lighter contact on the board (perhaps) is going to be the ticket. I'll be honest I sometimes use a gyuto for bread and the real danger is in the end of the cut in my experience. Finishing a cut in bread it is just so easy to overdo it on the board.

gladius wrote: ↑Thu Feb 18, 2021 6:14 pm I've seen it happen. There are knives whose edge is too fine and acute to cut dense bread. Use a bread knife.

+1. Actually, I just bought a Victorinox 10" knife, and even that thick, soft edge got lots of microbends when I used it to quick-slice a loaf with the factory edge. Looked pretty similar to yours. Factory edges can be fickle, but also, bread is just mean to knives (and I often prefer to use non-bread knives to slice a loaf...but I got to admit what it true).

It could be the factory edge. Try giving it a full progression sharping and see if that helps. I have had to this on some knives I have.

Thanks for all the help, I'll redress the edge, stop using it on bread and go from there.

S Tanakas, especially in ginsan are pretty thin behind the edge. It's probably less of an issue about the material/edge and more the bread like others have mentioned.