Small dark mark on tanto, kezu it just rust? Something else?

[terminus]

Hi,

 

I was wondering if anyone know what this small dark mark on this tanto is. Circled in blue. Is it a forging flaw and therefore considered a Kezu? Or rust? Or something else? (The other side is pretty much perfect). 

 

 

[Surfson]

Can you get a close up photo Tony?  Can't really see it well.

[terminus]

Hey Robert, unfortunately that’s the best photo I have. Here’s a clearer one but not as close up though. You can see the dark dot. 

[PNSSHOGUN]

Very difficult to ascertain what it is from the photos, best guess is a small Kizu.

[terminus]

Here’s another not exactly helpful photo:

If it is a Kezu, could it be a small fukure or shingane? 

[Shugyosha]

Could be a small rust pit or spot. Is it only on the surface or is there some depth to it? Might be a small fukure that has burst - again there might be some depth to it if so. It should be the same colour as the rest of the steel if intact.

 

Might be a small delamination, don’t think it’s shingane as the area is too small - would normally show over a wider area. 
 

It could be a carbon inclusion in the steel, but they are normally smaller and near the hamon so probably not. A last option would be something called sumigane seen in Hizen and Rai blades but that is broader and more like ink as the title suggests so I don’t think it’s that. 

[Shugyosha]

There's more on sumigane here - it's a term used to describe the shingane seen seen in Rai and other swords so please disregard the comments above. https://markussesko.com/2015/05/05/kantei-2-jigane-jihada-1/

[Bruce Pennington]

Don't know if this is clear enough.

[Surfson]

Looks like it is just a color change, and no change in the surface height or roughness of the blade, is that right?   I wonder if it is an irregularity in the composition of the steel?  Has it always been this way since you owned it?  

[terminus]

1 hour ago, Surfson said:

Looks like it is just a color change, and no change in the surface height or roughness of the blade, is that right?   I wonder if it is an irregularity in the composition of the steel?  Has it always been this way since you owned it?  

Correct, there’s no change in surface height or toughness. But a color change in that small spot. Has always been this way. Is that still considered a Kezu?

[Japan2112]

carbon pocket?

[ROKUJURO]

Tony,

probably not a KIZU, just a little lump of not perfectly homogenized steel, I think. It would not disturb me if it were mine, unless it was a very, very valuable blade.

[Surfson]

I agree, not a kizu.  May be a spot that is rich or poor in carbon leading to a darker steel.  For you metallurgists out there - which is darker, high carbon or low carbon steel?  

[terminus]

Just got a very good close up of it. Seems like a kitae? Not in the best mirror polish. 

[ROKUJURO]

Tony,

KITAE is the inner structure of a blade. KITAE WARE is a visible defect in the welding of the steel components which can show in different forms, often longitudinal fissures. 

You do not want a 'mirror polish' in that place, you want to see the HADA.

[SteveM]

Hello Tony,

I think you are obsessing over this spot, when it literally is nothing to worry about. It's just a dark spot. It's not a kizu, not a ware, not any kind of fatal flaw or any other defect that would cause anyone to take pause. You have a beautiful tantō, and you should enjoy it for what it is. It is a handmade work of art, made from the rawest of materials. The shape, the hamon, the horimono, the jihada, the bōshi, the tip, all look lovely. 

[Ken-Hawaii]

Agreed. Just a slight discoloration, with no intrinsic problem. You must be young, Tony, as my eyes would have skipped right over it.

[dkirkpatrick]

Guys, much more damage than we realize here.  Luckily, I’m in the market for unsightly blades such as this, perhaps you’d like to sell this quickly before it gets any worse 😆!
 

Ha, Nice blade,

 

Doug

[terminus]

hahaha, thanks guys! Yea I was obsessing over it since I was worried it might be considered a "kezu" since I honestly haven't seen one in real life before (luckily). Good to know it's nothing at all to worry about. 

[16k]

Not a kizu for me. A sumigane or an inclusion of some sort. Maybe the skin is thinner in that spot and what you’re seeing is the softer core steel, but not a kizu. I like the blade by the way.

[Jacques]

IMHO it looks like a little heterogeinity in the steel. 

[PNSSHOGUN]

Could even be a spot where the Saya has rubbed a little.

[Oshy]

Yea this blade is shot, send it my way 😀

[Tom Darling]

I can't make out the mei or date?   Nice piece.  

 

 

Tom D.

[terminus]

On 9/8/2020 at 10:19 AM, Tom Darling said:

I can't make out the mei or date?   Nice piece.  

 

 

Tom D.

Thanks! The tanto is made by Kanbayashi Tsunehira and the horimono by Yanagawa Senju. Both signed.