Ichimai Boshi?

[Jnuzzo]

Just got this in hand and a little stumped on the boshi.  Hamon seems to vanish at the yokote, but kissaki seems uniform and more matching of the yakiba than any other metal of the blade.  Is this what an ichimai boshi looks like or is this just an effect of  polish?

 

Added a couple close up photos of the hamon as well.  
 

apologies n thanks, I’m a noob.  

[klee]

The polish is just rough. The boshi is pretty clear in this one photo.

[Jnuzzo]

Would it be where the light / dark sort of reverses in that photo (darker areas of kissaki are the boshi outline)?

[klee]

Hi @Jnuzzo

 

Yes the darker area is hardened steel. You have to play with the light a bit sometimes for out of polish blades to see it.

 

 

[Jnuzzo]

41 minutes ago, klee said:

Hi @Jnuzzo

 

Yes the darker area is hardened steel. You have to play with the light a bit sometimes for out of polish blades to see it.

 

 

Ah I can kinda see … granted the polish and tiny kissaki make it rough on this one (along with my eyesight lol).  But it’s almost like you have to look through the metal in a way to see how it luminesces?

 

Educational question … is it always apparent in the topology of the metal as to how it was tempered, or do some things not show through in that manner when the polish is off, and you have to look to lighting to “see through it” so to speak?
 

Like when I see blatant nie or hada grain or a distinctly differential nioi … it’s apparent in the topology even in a tired polish … but like with this boshi, in some light the topology looks congruent, and in other lighting there are patterns and differentiations that seem to emerge.  
 

Like am I missing something when I look at the metal in the lighting of these attached photos, or are the things I’m looking for just not apparent here?
 

Thx, Jeff

[ROKUJURO]

Jeff,

in a true ICHIMAI BOSHI, you will not see a HAMON. In most cases, the HAMON will be getting wider towards the YOKOTE so that it fills the width of the JI.



I have a blade with ICHIMAI BOSHI, but it is difficult to catch in a photo. Maybe I can try tomorrow.

You wrote;....is it always apparent in the topology of the metal as to how it was tempered....

TEMPERING is not HARDENING! Tempering (YAKIMODOSHI in Japanese) does not produce a HAMON, but hardening through quenching (= YAKIIRE) in water does.

[Jnuzzo]

47 minutes ago, ROKUJURO said:

Jeff,

in a true ICHIMAI BOSHI, you will not see a HAMON. In most cases, the HAMON will be getting wider towards the YOKOTE so that it fills the width of the JI.



I have a blade with ICHIMAI BOSHI, but it is difficult to catch in a photo. Maybe I can try tomorrow.

You wrote;....is it always apparent in the topology of the metal as to how it was tempered....

TEMPERING is not HARDENING! Tempering (YAKIMODOSHI in Japanese) does not produce a HAMON, but hardening through quenching (= YAKIIRE) in water does.

Gotcha!  And yes I totally misused the term tempering  🤦🏻.  
 

Does the kawagane fully encapsulate the shingane on a nihonto, or are sections of the ji / mune left as shingane?  I.e., does an ichimai boshi create a distinct look on the ji / mune portion of the steel that is hardened via yakire?

[klee]

Technichally speaking yes the kawagane surrounds the shingane in one form or another depending on the construction. Many earlier koto swords do not have shingane at all. 

 

But visually it isnt obvious sometimes.

There are nuances within the kawagane that makes it hard to distinguish at times. And sometimes in well made swords, the shingane itself is very fine and well forged and hard to distinguish. 

 

 

It s generally accepted that koto blades will have some core steel. It s a sign and testament to age and not a flaw caused by the skill of the smith

[ROKUJURO]

As Kevin wrote above.

There are many blades showing fine fissures on the MUNE, and some collectors are afraid that this might be flaws. But it is just a welding-seam on blades where the SHINGANE has not been encapsulated completely. This is done on purpose to leave the MUNE somewhat softer than the rest of the blade to block or deflect an opponent's strike.

Comimg back to ICHIMAI-BOSHI, this is a feature that has mostly to do with TSUCHI-OKI (= application of clay before quenching/YAKI IRE). As described above, you can create a fully hardened KISSAKI by widening the YAKIBA when it comes close to the YOKOTE. Often in this case, the HAMON makes a more or less sharp turn back so it does not appear in the KISSAKI. 

Depending on the polish, you would not always identify an ICHIMAI BOSHI by looking at the MUNE, but if the TOGISHI used HADORI, this could be more obvious.
 

[ROKUJURO]

I tried to make photos of the ICHIMAI BOSHI but I could not capture it properly. Instead, I drew a 'fictious' line of how the HAMON goes.