Is this acid polishing?

Polishers finishing blades with acid has been a controversial topic in Japan, but nevertheless it is already known that there are many polishers who use mild acid in the finishing stages to please their customers. Sometimes it makes sense in order to cut costs of polishing a poor blade but other times it is done on high end pieces as well. Is this an example of a poor one?

hard to say from these photos.

It is hard to tell but from the coloration bluish greenish on the second picture I would think it is artificially placed rather than due to the polishing stones

Sorry, I can't provide additional pictures because it isn't my sword. Aoi is selling it: http://www.aoijapan.com/katanataira-nagamori-saku

In my view, the hamon looks etched and too visible. There are areas where it looks white and then becomes dirty brownish. That is one of the signs of poor acid polishing.

First of all : The coulor of neitehr the ji or ha can be juged by these photos.

Is the hamon to clearly visible ?

I do not think so, it is not unusual to have a strong boundary and with the usage of the correct stone it is quite easy to produce an clear white line. (I do not talk of the hadori border to the ji )

Regarding this blade : The foundation polish alone seems not to be nice. The lines do have a slightly sluggish, rounded look.

Greets

Stefan

Hi there,

I am very familar with all techniques used to make a hamon are in modern production katana’s, it is a different level of details for sure, but some of them are really skilled. Also I know from literature some Japanese pollishers also use additional polishing techniques, I also do a lot of talking with forges and some of them have really good knowledge of older techniques. Most of them are really to save time and money, as you already mentioned.

I probably think the hamon is real down under, but they used probably polishing with nitric acid or tanpan polish to make it more bright because after the standard hadori polish it was still to weak or unactive in the polisher his eyes. The Tanpan polish is done with copper sulfate dissolved in water, they used boiled water for this. The bring on cotton wool this copper sulfate on the blade surface. The moslty used a uchigumori Ji Stone to polish it in a different color, this probably has happened. The nitric acid polish makes it more white so I doubt they used this technique. Those are my thoughts for the moment.

Hi there,

 

I am very familar with all techniques used to make a hamon are in modern production katana’s, it is a different level of details for sure, but some of them are really skilled. Also I know from literature some Japanese pollishers also use additional polishing techniques, I also do a lot of talking with forges and some of them have really good knowledge of older techniques. Most of them are really to save time and money, as you already mentioned.

 

I probably think the hamon is real down under, but they used probably polishing with nitric acid or tanpan polish to make it more bright because after the standard hadori polish it was still to weak or unactive in the polisher his eyes. The Tanpan polish is done with copper sulfate dissolved in water, they used boiled water for this. The bring on cotton wool this copper sulfate on the blade surface. The moslty used a uchigumori Ji Stone to polish it in a different color, this probably has happened. The nitric acid polish makes it more white so I doubt they used this technique. Those are my thoughts for the moment.

Don´t think so.

Just take a fast look in the book " the art of Japanese sword polishing" by Takaiwa Stetsuo, page 136.

"Water with cooper sulfate is applied to the ji wtih a Q -tip or Cotton wool while carefully avoiding wetting the hamon.

THE HAMON WILL FADE if the water and cooper sulfate reach it."

Well, I tried it out on a brocken blade without kissaki ...it is true. The hamon fades.

By the way : Ji-To means Stone for the ji, not ha. The ha is never polished by jito, only by variants of hato.

Greets

Stefan

What is the, I think you will call it ratio, I once saw a blade with this copper techique and you some colors in the hamon, this gave me a thougth they used it, but honestly I must tell you I was not there

But you will have some ashi naga (the longer lines or patterns ) and those can probably end in the hira-ji, here you can have some reactions, do not know. But when it totally will disappear the hamon the probably have not used this, but you can use it in different ratios, but I am curious what they have used to make those different colors.

But you will have some ashi naga (the longer lines or patterns ) and those can probably end in the hira-ji, here you can have some reactions, do not know. But when it totally will disappear the hamon the probably have not used this, but you can use it in different ratios, but I am curious what they have used to make those different colors.

Do you mean "naga-ashi" ? ( Ashi that are nearly reaching the hasaki. Typical in shinshinto blades. )

Thereare no ashii flamening into the ji...Such tips in the hamon are known, far as i know, as togari etc.

Ashi are always pointing toward the hasaki.

Colours in the Yakiba : They have nothing to do with acid or tampan polish. They are there as the different colours of nie are.

By example : Black nie ist a sign of later blades in most cases while brilliant white without clustering is in most cases a sign of an fine Koto or Shinto.

Colours in the area of the ha :

Why not ?

It is also differently forged steel, even hardend.

Therefore different colours can appear in the yakiba as a result of tempering and folding the material.

Greets

Stefan

I do not agree, colors in the area in the Ha are not common. Polishers mostly want to bring out clearly the Ha, so the Hadori stones, right? Some of them use hazuya. Those are producing white, contrasting edges, you probably will see this when you check most of the Japanese sword vendors. I have seen some Nihonto and mostly the are white, right? I do not know if they used a special kind of lamp, with some special nano meter. Basicly ashi are softer steel (pearlite) coming into the harder steel, so the chip will stop at the ashi line, a part of the hamon. All due to bringing on the claymixture with quenching. The folding will only make contrast between layers, no colors as far as I know.

I do not agree, colors in the area in the Ha are not common. Polishers mostly want to bring out clearly the Ha, so the Hadori stones, right? Some of them use hazuya. Those are producing white, contrasting edges, you probably will see this when you check most of the Japanese sword vendors. I have seen some Nihonto and mostly the are white, right? I do not know if they used a special kind of lamp, with some special nano meter. Basicly ashi are softer steel (pearlite) coming into the harder steel, so the chip will stop at the ashi line, a part of the hamon. All due to bringing on the claymixture with quenching. The folding will only make contrast between layers, no colors as far as I know.

Well.....

Hatsuya and Hadori stones are both slices of Uchigumori hato Stones with the same purpose. It is simply the same.

The White of the hadori has nothing to do with the colours in the ha and the hardend area.

In the hadori process the ha ist roughend a little bit, therefore it does look white in contrast to the ji.

That´s all in simple.

Your comment about ashi is simply wrong.

Aahi are "cutting" through the layerd construction of the blade verticaly. They are mostly visible as whtie lines,nevertheles the Yakiba is blue, black or whatever.

One of the signs of poor acid polishing is a yakiba that is white in frontal view and then turns to a dirty brown color when tilted in different angles. That's what I'm seeing in these photos aside from the strong look which appears etched IMO.

 

I probably think the hamon is real down under, but they used probably polishing with nitric acid or tanpan polish to make it more bright because after the standard hadori polish it was still to weak or unactive in the polisher his eyes.

Yes, I thought so too. Good post, btw.

With tanpan polishing the hamon does not become brighter.

That is not my opinion, that is an simple technical fact.

I am pretty sure that an expert kenmashi like Setsu Takaiwa knows more about the background than we do.

The next thing :

It is the goal to make the boandary brighter, the hamon.

Th Yakiba is not the hamon.

Yakiba = hardend area, hamon borderline between ha an ji.

Another joke : In the example blade the blade has been polished in hadori-style. Therefore, if it is only halfways profesionell done, the Brown hue in the area between the Hamon and the Ha-Saki disappears. No brownies there ( I couldn´t resist this joke ).

The hatsuya removes the brownisch cast in the yakiba.

But hey, stired it all also up in future, You will have much fun here...

By the way : If You know all these things : Why You are asking ?

Yes, I agree the Hazuy and Hadori stones are uchigumori, but they have different purpose, the hadori is most finest, smallest and does not have any sharp angles. So they are prepared different, so you will have different results otherwise they will not have the step by step technique. So this will effect the hamon and the habuchi, like said before the polishers wants to bring out the hamon clearly. The effect on the jizuya stone, it turns out to be more white, right? You also have some different hardness between “in” the stones, so this will affect also.

I am not pretty sure how the tanpan polishing will effect the area from shinogi to hasaki if you use it with lower ratio, it will effect the hamon with colors like I told you. But it is speculaiton because I have not been there. The tanpan technique is basicly something more for the Ji-hada but used on the entire blade between the shinogi and ha, you will have colors coming up, it is something I have seen at a chinese forge. Japanese polishers will probably use different techniques not all out of books, but will sometimes give it a try, I suggest.

The white Hamon is something NBTHK really want to see in my opinion, and diffent colors will not occur due to folding the steel, this really is wrong, I have seen hunderds of folded “chinese” katana’s and I have never seen this, so I am just telling from my own experience.

Ashi are really coming from the mune, so it is obious they are more softer, I do not think I have to tell you all the advantages of differential hardening. It really is softer steel embedded in harder steel, so you are really wrong about this, even the chinese forges do understand this very clear. I will look this after when I am back from my work.

I am always traveling and picking up knowledge, I do not ask anything, just giving my thoughts.

 

The next thing :

It is the goal to make the boandary brighter, the hamon.

Th Yakiba is not the hamon.

Yakiba = hardend area, hamon borderline between ha an ji.

Yes, Yakiba is hardened area or "Ha". Looking at it again, the browning occurs in the nioiguchi as well, so it's the entire hamon.

By the way : If You know all these things : Why You are asking ?

Because my judgement/opinion isn't always right. So I'm looking for different opinions and to make this an educational topic about acid polishing (which not many collectors know about). Thanks for posting your knowledge.

O.K.

Regarding Tampan togi : Just try it out on broken blades. There are pretty eough around, broken pieces with nakago but no kissaki.

I use thes pieces for studies the effects of polishing techniques. It is much easier to jugde a polish if You know what is happening.

That solves many Problems, in , my humble point of view.

Greets

Stefan

Yes, I agree the Hazuy and Hadori stones are uchigumori, but they have different purpose, the hadori is most finest, smallest and does not have any sharp angles. So they are prepared different, so you will have different results otherwise they will not have the step by step technique. So this will effect the hamon and the habuchi, like said before the polishers wants to bring out the hamon clearly. The effect on the jizuya stone, it turns out to be more white, right? You also have some different hardness between “in” the stones, so this will affect also.

 

I am not pretty sure how the tanpan polishing will effect the area from shinogi to hasaki if you use it with lower ratio, it will effect the hamon with colors like I told you. But it is speculaiton because I have not been there. The tanpan technique is basicly something more for the Ji-hada but used on the entire blade between the shinogi and ha, you will have colors coming up, it is something I have seen at a chinese forge. Japanese polishers will probably use different techniques not all out of books, but will sometimes give it a try, I suggest.

 

The white Hamon is something NBTHK really want to see in my opinion, and diffent colors will not occur due to folding the steel, this really is wrong, I have seen hunderds of folded “chinese” katana’s and I have never seen this, so I am just telling from my own experience.

 

Ashi are really coming from the mune, so it is obious they are more softer, I do not think I have to tell you all the advantages of differential hardening. It really is softer steel embedded in harder steel, so you are really wrong about this, even the chinese forges do understand this very clear. I will look this after when I am back from my work.

 

I am always traveling and picking up knowledge, I do not ask anything, just giving my thoughts.

O.K.

You are right. hazuya and hadori Stone are both uchigumori. is one finer ?

No !

In most cases after the last "big-stone" the Jito all is visible.

The restof the process ist cosmetic to produce an pleasing Picture.

If been told by a togishi that is a good idea to round of the corners in hazuya in all steps.

Jitsuya : A critical stone. it can easily destroy the face of the blade.

Darkness is not the desireable Thing. We want colour as Mr. Bohay said so many years ago.

Some of the later Mino-bnlades are nearly blid in the surface, owari is dark blue like a sky in summer. Early soshu ?

Like an "Marmorkuchen" (i don´t know the englisch word for it )

Here we are at the colour Point of tetsu.

Ji-Tetsu ist ot Ji-Hada.

Tetsu is the steel where the hada is made of.

Take look on Norishige, Hankei, Satsuma-Mono...All are full of colours.

Indeed, these are fine points, but essential in kantei.

Chinese blades :

Yes, folding mono-steel in layers is nonsens. But this is the Thing the chinese mostly do. They fold industrial steel.

Therefore no colours.

On the other hand the old Japanese : They were forced to work with different qualities of metal, therfore we do have these colours.

Same with the hamon

It is usefull to produce allways a "crying " hamon : No.

By example.

Many lesser Sue Seki kaji are known for their mild tempering. So it should be polished in this way, that means not to loud..

Of course there are many things written in the books, but i do strongly believe that the good old "give it a try" system is even in the togi-world still at work.

Many, many years ago i did have a talk to Matsumura Sensei. I asked him "is this and that true ?" Well he smiled an showed me some things.. None of which is wiritten in any of those books, neither english or Japanese.

But why not ?

To say it with the old german Chanceler : "Es zählt was dabei rauskommt ! " ( the result counts, nothing else" )

Regarding Ashi :

You are absolut right, they come done from the mume ! But we can see tthem only in the Yakiba.

If You take now the sunagahii-system into your account, how brilliant is that ?

Nearly perfect in an selctiv hardend blade.

Greets

Stefan