Fake Hamon

To reveal the possibility of a fake hamon I tested one of my swords that was sold to me as "differentially tempered with real hamon"

In a few steps I will try to show how you can test this for yourself

This is the sword I will examine, it is a 1060 steel sword with a o-kissaki (3 inch).

As you can see in the images the hamon is quite prominent which can be attributed to an acid enhancement of the real hamon. Another option is that the forge used a so called "wire brush" where a spinning wheel of metal wires cause a hamon effect because of the abrasive effect of the wires. The first effect can be seen in swords from the Paul Chen/Hanwei forge in Dailan, China. The latter effect is mostly found in the lower end swords of different Chinese forges (Masahiro, etc.).

The sword I bought showed a typical "wire brush" hamon and to prove this I have tried to remove some of the hamon that is located under the habaki. because i did not want to affect the current "hamon" I chose a spot that is not visible when the sword is fully mounted with habaki and the other fittings.

The first images are the sword itself. More images can be seen here

Clearly visible is the hamon with some faint lines indicating the scratches from the wire brush

Here is the part I chose to remove the hamon and to re-polish the piece. The hamon seems extremely white but this is due to the bright halogen light I used to make the pictures. In real life the hamon looks more like the pictures above.

First I used a course abrasive (600 grit sanding paper) to remove the original polish and the suspected wire brush. With this method you will not remove the actual hamon (when the sword is differentially tempered) because the hamon is a physical characteristic of the steel.

Then I masked the parts which I did not want to re-polish and I proceeded with a less coarse sanding paper (800 grit)

Then a 1200 grit sand paper

And then a treatment with the polishing machine with first blue polishing paste and finishing it off with some white polishing paste

The final result: The hamon fully disappeared indicating a possible fake hamon. I'm aware that a polish can also remove the characteristics of a real hamon so an additional test could be an option..

To bring out the hamon after the polishing I used an acid treatment with citric acid and some dish wash liquid (to increase viscosity). Next I heated the mixture  in the microwave, because heat accelerates chemical processes.

First I removed all residual oil with some acetone. and I gently applied some of the hot acid onto the blade with a cotton-swap (wattenstaafje)

first image is the degreased blade and second image is the development of a whitish stain. This stain was formed after a treatment of 10 minutes with the acid liquid.

After cleaning the acid-treated part of the blade the following images can be seen (made in slightly different angles):

Clearly visible is a faint hamon where the original wire brush hamon was. If this is still the effect of the wire-brush hamon is not clear, fact is that there is no wire-brush effect in the new acid enhanced hamon. and the "new" hamon does not fully correspond with the original wire-brush hamon (see images above). You can also distinguish a small line in the upper part of the hamon, maybe this is the effect of the forging process of the sword-smith when he removes the clay from the blade before tempering to get a wave like hamon?

It could be that the blade was initially differentially tempered but because of the relatively soft steel the hamon did not become very visible after polishing. To show that there is a hamon they decided to add an artificial hamon. Why they did not use an acid enhancement is another question to be answered.

to be continued...

The discussion of this topic can be followed here:

Sword forum Benelux (in Dutch)

or here:

Sword Forum International (in English)