Japanese sword bevel angle

J

junhei

Joined
Aug 2, 2022
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2
Hello everyone. A simple enough question, or so I thought. But now I'm 30 minutes into searching this on google, and despite expecting that I will find 10 results on the first page, I haven't found anything concrete or trustworthy.. Also, if this forum has a search function, I apologize but I have not been able to find it. So at this point I figured I'd just make an account and flat out ask. If someone who owns actual antiques and has measured the bevel angle(or just knows from other trustworthy sources) can take a short few seconds out of their day and tell me I would appreciate it a lot. I have a tanto and wakizashi planned and despite using non-traditional methods and materials, I want the geometry and construction to be as close as possible to traditional. I'm sure there is quite a variation. I don't necessarily need an all encompassing answer, just an angle that was for sure typically used.
Thanks!
 
Welcome to the forum Junhei. My guess is that you are probably right in thinking there was a variation in angles. You also might want to specify whether you are referring to edge bevel or primary grind bevel. As for what was "traditionally typical", I have no idea what angle that could be. But who doesn't love answering a question with a question: WHY do you want your geometry to be "typically traditional" if you are not using traditional methods and materials? Do you agree that modern materials and methods will be able to yield an edge that can support thinner geometry while also being every bit as strong or stronger than a piece made with traditional materials and methods?
 
Japanese edges have a convex grind so I don't really know how to answer that question. The bevel starts st maybe10 degrees and goes to about 40 degrees at the cutting edge...
 
David Mary said:
Welcome to the forum Junhei. My guess is that you are probably right in thinking there was a variation in angles. You also might want to specify whether you are referring to edge bevel or primary grind bevel. As for what was "traditionally typical", I have no idea what angle that could be. But who doesn't love answering a question with a question: WHY do you want your geometry to be "typically traditional" if you are not using traditional methods and materials? Do you agree that modern materials and methods will be able to yield an edge that can support thinner geometry while also being every bit as strong or stronger than a piece made with traditional materials and methods?
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I'm not opposed using traditional methods and materials, but they are too inaccessible and difficult. No doubt modern materials are more performant, but even so I would prefer it have the traditional geometry and be more resilient, than perform better and have roughly the same resilience. The main reason being that I just like the aesthetic. And since we have surviving antiques in excellent condition, with hardly a spec of rust on them, despite being hundreds of years old, the aesthetic is very well defined. Also I will probably cut some tatami mats at some point and I want it to feel as close to what it would feel like to swing a historical example. The bevel angle is too hard to determine from pictures though. The length, thickness, taper, curvature, width is easily determined from pictures and I can find direct numbers as well, except for the angle for some reason....
Triton said:
Japanese edges have a convex grind so I don't really know how to answer that question. The bevel starts st maybe10 degrees and goes to about 40 degrees at the cutting edge...
Click to expand...
Thank you for this. From my research I found out that some were convex and some were flat, and they never came with a secondary bevel, at least not straight from the "factory". Also the Japanese had their armor piercing tantos as well, akin to the European rondel daggers, which were extremely thick. I'm guessing those were among the convex ones. But I'm looking for something that can slice, and I would prefer the flat version since it's gonna be easier to make and I can get the grind line more crisp. 10 degrees to 40 degrees seems like whole lotta convex. Also 40 degrees seems like a pretty thick edge for a slicer, but I guess it has the function of a secondary bevel.... May I ask what is your source?
 
Glad to see you know what you want and why!
 
junhei said:
I'm not opposed using traditional methods and materials, but they are too inaccessible and difficult. No doubt modern materials are more performant, but even so I would prefer it have the traditional geometry and be more resilient, than perform better and have roughly the same resilience. The main reason being that I just like the aesthetic. And since we have surviving antiques in excellent condition, with hardly a spec of rust on them, despite being hundreds of years old, the aesthetic is very well defined. Also I will probably cut some tatami mats at some point and I want it to feel as close to what it would feel like to swing a historical example. The bevel angle is too hard to determine from pictures though. The length, thickness, taper, curvature, width is easily determined from pictures and I can find direct numbers as well, except for the angle for some reason....

Thank you for this. From my research I found out that some were convex and some were flat, and they never came with a secondary bevel, at least not straight from the "factory". Also the Japanese had their armor piercing tantos as well, akin to the European rondel daggers, which were extremely thick. I'm guessing those were among the convex ones. But I'm looking for something that can slice, and I would prefer the flat version since it's gonna be easier to make and I can get the grind line more crisp. 10 degrees to 40 degrees seems like whole lotta convex. Also 40 degrees seems like a pretty thick edge for a slicer, but I guess it has the function of a secondary bevel.... May I ask what is your source?
Click to expand...
I've never seen a flst ground traditional Japanese blade although admittedly its not my area nor have I seen them all.

That said there is a good article here:

 
Bevel angle?

I had thought that the traditional Japanese swords have a convex edge geometry rather than an actual bevel.

Did I get that wrong?
 
VorpelSword

You are correct for antique swords (modern swords vary). It is called "niku". see article on my Japanese sword website linked above.
 
VorpelSword said:
Bevel angle?

I had thought that the traditional Japanese swords have a convex edge geometry rather than an actual bevel.

Did I get that wrong?
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As Rich noted you got it right. I suggested as much above. I think our OP, was wanting someone to tell him that putting some sort of edge bevel on his sword was accurate. So far as I know it is not. I suspect that our OP is long gone now though.
 
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