Japanese knives can you evaluate the type of steel visually?

[Odissea/1978]

Hi everyone, can someone explain to me how the steels on Japanese knives are visually distinguished?
I have been restoring straight razors for a few years now and now I would like to start with knives; I find it very difficult especially on auction sites to be able to understand what is quality and what is not, given that I have "studied" the kanji of the most famous producers to try to orient myself.

the question of steel, however, remains even more difficult for me to understand, the only distinction I understood is Honyaky and laminate and here we are.

thanks to whoever wants to help me

 

[ian]

It’s generally impossible to identify steel type from pics. You can distinguish san mai (or more general laminated constructions) from monosteel by the lamination line, you can often distinguish monosteel from honyaki (monosteel heat treated so the spine is softer than the edge) by the presence of a hamon (an often wavy line higher up the blade that is the boundary between hard and soft steel), and you can distinguish carbon steel from stainless if it has a patina, but not otherwise. If you can read kanji, once in a while it’ll actually say the steel type.

Usually one tries to distinguish quality knives from bad knives by looking at other features of its construction, but that’s kinda hit and miss. Maybe if you post some examples here people can chime in with “crap” or “not crap”.

 

[Odissea/1978]

It’s generally impossible to identify steel type from pics. You can distinguish san mai (or more general laminated constructions) from monosteel by the lamination line, you can often distinguish monosteel from honyaki (monosteel heat treated so the spine is softer than the edge) by the presence of a hamon (an often wavy line higher up the blade that is the boundary between hard and soft steel), and you can distinguish carbon steel from stainless if it has a patina, but not otherwise. If you can read kanji, once in a while it’ll actually say the steel type.

Usually one tries to distinguish quality knives from bad knives by looking at other features of its construction, but that’s kinda hit and miss. Maybe if you post some examples here people can chime in with “crap” or “not crap”.

Thanks for the very useful answer! I thought there were more "clear" references, in reality it is much more random than what I imagined also because the photos are often horrible. I will try to base myself on the geometry if it is clear enough and on wear, as soon as I get the first two knives I bought I will post them here, let's see what junk I bought

 

[miggus]

Frankly, I think most people, unless they are super experts, will have a hard time narrowing down the steel type too much even if they have the knife in hand. Sure, you can easily see how stainless it is, approximate hardness and whether if its high or low alloy. With a lot of experience, you probably can also tell if it is a certain group of alloy, i.e. high vanadium or not.

But beyond that - how man of us could certainly tell if this unknown knife is W#1 or AS, badly done SG2 or well exectuted VG10? And those are already quite different in composition.

But especially if all these complicating factors with lots of heat treatment options come into play. Not to mention rarer steels or ones that are closer together.

Sure, there is a few savants out there and maybe with lab equipment you can also do a lot. But the ordinary knife nerd who is not a smith... phew.

 

[Ericfg]

Even with Western knives (which I collect) it's sometimes hard to differentiate carbon steel blades (polished, without patina) and stainless steel. You've got the profile, scale attachment method and logo to help with clues for IDing but even I get fooled sometimes.
But, as with most things in life, the more you become familiar with things the better you get doing that task. Practice makes perfect.

 

[miggus]

Interesting perspective Eric. I wonder if there are people out there who can reliably tell if a knife is made from Aogami or Aogami Super, for example. I personally doubt it, but I have no further metallurgical knowledge, so I'm guessing here.

 

[Odissea/1978]

Frankly, I think most people, unless they are super experts, will have a hard time narrowing down the steel type too much if they have the knife in hand. Sure, you can easily see how stainless it is, approximate hardness and whether if its high or low alloy. With a lot of experience, you probably can also tell if it is a certain group of alloy, i.e. high vanadium or not.

But beyond that - how man of us could certainly tell if this unknown knife is W#1 or AS, badly done SG2 or well exectuted VG10? And those are already quite different in composition.

But especially if all these complicating factors with lots of heat treatment options come into play. Not to mention rarer steels or ones that are closer together.

Sure, there is a few savants out there and maybe with lab equipment you can also do a lot. But the ordinary knife nerd who is not a smith... phew.

Sure, it's all perfectly reasonable. in reality I was just curious to know how they choose the knives when they buy them at auctions because I often hear about this or that steel but evidently it is information that you have a priori from the sellers and on which your trust is based.

 

[Odissea/1978]

Even with Western knives (which I collect) it's sometimes hard to differentiate carbon steel blades (polished, without patina) and stainless steel. You've got the profile, scale attachment method and logo to help with clues for IDing but even I get fooled sometimes.
But, as with most things in life, the more you become familiar with things the better you get doing that task. Practice makes perfect.

of course you are absolutely right, I'm trying to familiarize myself with the kanjii let's see if I learn something more. just today I found the first good knife up for auction

 

[miggus]

Sounds great! Good luck with your endeavor, with some adventure spirit there are great blades to be found out there.

 

[Delat]

Interesting perspective Eric. I wonder if there are people out there who can reliably tell if a knife is made from Aogami or Aogami Super, for example. I personally doubt it, but I have no further metallurgical knowledge, so I'm guessing here.

Some very experienced sharpeners could probably tell once they got them on the stones. About all I can tell personally is low-alloy carbon vs high alloy stainless like SG2 or VG10 though. And that’s only because of how quick white and blue type steels sharpen.

 

[Pie]

Captain obvious says sometimes you get lucky and they stamp/chisel it on the back. As mentioned sometimes there’s a mark or symbol.

White 1 and white 2 for example

I think moritaka only uses this symbol for blue 2 (NBC logo looking thing on the left). I’m probably wrong on that but I remember it’s not on the AS ones.

 

[miggus]

I’m probably wrong on that but I remember it’s not on the AS ones.

You're right. No NBC symbol on Moritaka AS knives.

 

[ethompson]

Do I think I could tell white 2 from white 1 or white 2 from blue 2, nope… Aogami Super does tend to have a visible defined grain structure at very high levels of jnat polish, so that could be a hint if I knew I was looking for one.

 

[Odissea/1978]

Captain obvious says sometimes you get lucky and they stamp/chisel it on the back. As mentioned sometimes there’s a mark or symbol.

White 1 and white 2 for example
View attachment 222470View attachment 222468
I think moritaka only uses this symbol for blue 2 (NBC logo looking thing on the left). I’m probably wrong on that but I remember it’s not on the AS ones. View attachment 222469

Thanks super useful info

 

[Odissea/1978]

Do I think I could tell white 2 from white 1 or white 2 from blue 2, nope… Aogami Super does tend to have a visible defined grain structure at very high levels of jnat polish, so that could be a hint if I knew I was looking for one.

Thanks, any additional information makes it clearer, I'm used to polishing but I do it with abrasive pastes and diamond paste, the result is certainly less nuanced than the Jnat.