Is this hamon due to the polish, or the forging?

[Gerry]

I sometimes see blades with a hamon that is very unique, almost acid etched; example below:

 

 

My question is...it looks like the hada is especially pronounced on a blade like this, so is it due to the way the polish was done, or is it because the hada is especially coarse?

 

[Rivkin]

Its a modern, shinshinto or later blade - very long, high contrast lines which are however pure nioi.

This being the case, the blade reacts well to acid, but at the same time even normal polish can look acid etched. I think the polish here is ok, its mostly the blade which contributes.

[Tohagi]

... it looks a little "Too much" to me.

 

Usualy a professionnal Togishi will choose an elegant contrast between hamon and Ji gane: first time I see such a flashy pop up hada...

 

Is that an effect of the picture or the blade looks the same in hand?

[ROKUJURO]

On 7/30/2024 at 11:29 PM, Gerry said:

I sometimes see blades with a hamon that is very unique, almost acid etched.....it looks like the hada is especially pronounced on a blade like this, so is it due to the way the polish was done, or is it because the hada is especially coarse?...

You cannot produce a HADA by polishing that was not planned and executed by the smith. On the other side, a bad polish might hide the HADA and make it look plain.
Acid etching is often mentioned, but who has really seen it and knows facts about it? It is mostly used to enhance the HAMON and has very little effect on HADA.   

[Jacques D.]

To be clear : it cannot be seen on photos

[Matsunoki]

Maybe it’s a blade where the smith has forged differential steels in layers to give this effect, similar to Sendai Kunikane?

[Franco D]

3 hours ago, ROKUJURO said:

 It is mostly used to enhance the HAMON and has very little effect on HADA.

 

Hmm. 

 

From these images it is difficult to say for certain exactly what is going on here (the forging is the forging, the polish is the question). You have to actually see the color and finish of the steel to better judge without simply guessing. An acid polish while bringing out structure of the steel/forging including the hada, the steel itself will look dry and scaly. Once you've seen this dry scaly look it will become easily recognizable. There will be variation.

[Itomagoi]

Do you have pics from Nakago?

 

 

[Jacques D.]

As there is a lot of incomprehension about acid polishing this is well worth a read.

 

http://www.ksky.ne.jp./~sumie99/acid polishing.html