Hamon in Katanas & Other Japanese Swords

Hamon Choji

Hamon in Katanas & Other Japanese Swords


When it comes to katanas as works of art, the Hamon is one of the main focuses. But to talk about these patterns we first need to take a look at the process that gives rise to it.

In feudal Japan, swords were everything.

Originally forged with techniques learned from the Chinese, swords evolved in the hands of skillful Japanese blacksmiths into what today is a symbol of ancient weapons engineering: the katana.

But that was just the beginning.

Once the perfect weapon for the elite Japanese troops was found, the next step was to improve that weapon.

That’s how we came to, among other processes, the clay tempering.

And, more specifically, its artistic implications: the elegant, longed-for hamon lines left along the blade.

In this post we will talk about hamon in swords, how they originate, their patterns, and more.

Let’s begin!



What is Hamon?

The word “hamon” means literally “blade pattern”, and most of the time, that’s exactly what it is.

The hamon is a visual effect that runs along the blade. It borders the sharp edge (ha) and describes different shapes that are attractive to the naked eye.

It’s a whitish line or wake whose shape depends on the artistic skills of the blacksmith. As such, it makes the blade of a sword unique and distinguishable.

The hamon, with its elegant and shining curves, is desired by both Japanese sword lovers and experts. Actually, by anyone that can recognize in them the small subtleties of the blacksmith.

Experts in swords even used the hamon pattern to determine the veracity of some ancient blades attributed to the alleged hands of famous blacksmiths.

What makes the hamon especially famous is that it acquires an almost mythical status thanks to its translucent appearance; as if it were the soul of the blade.

This is not surprising considering that a reverential cloud of mysticism surrounds the traditional process of forging a samurai sword.

In addition to this, an original hamon is often synonymous with a good sword, as it is the result of the very important process of clay tempering.


Samurai katana sword with hamon
Click on the picture to see the sword


Clay Tempering: The Science of a Good Blade

Clay tempering is the ideal hardening method for all types of swords.

It is a complex process in which there is always a possibility that the sword will not hold and break.

Unlike heat hardening, during clay tempering, the sword blade is covered with a special mixture of clay that helps it to better contain the heat; a thicker layer on the body and a thinner one on the edge.

Every blacksmith has his special clay mixture, composed of different components that help it to do a more effective job.

After this, the sword is subjected to high temperatures of up to 900 degrees Celsius, and is then immersed in a container filled with water (or oil).

In doing so, the fire burns brightly. The flames rise as the steel dives into the liquid; they struggle to survive. On a microscopic level, the metal begins to mutate and acquire new properties.

Once removed from the water, the part covered with clay acquires a slightly more flexible consistency (perlite) than the cutting edge (martensite). This allows it to absorb shocks better without breaking.

In short, two metal end up composing the blade of the swords instead of just one.

A strong metal on the border of the blade to allow a sharp edge for longer, and a more flexible metal on the body of the blade, which helps it resist all kinds of impacts that might otherwise break it.

An almost collateral effect of this important process is the formation of the hamon, which is nothing more than the visible difference between the two types of metal found in the blade.


Samurai with sword practicing


Learn How to Know If the Hamon Is Fake

Learning to differentiate between authentic hamon and a fake one is crucial when acquiring a clay-tempered sword.

In fact, it is the only way to be sure at first glance that the sword you are buying is of good quality, and not a simple imitation.

For this you must know that, first of all, a fake hamon almost never will look like an original hamon. So if you sharpen your eye by seeing what real clay-tempered swords look like, then in time the difference will be obvious.

Take a look at our catalogue of clay-tempered swords to see authentic swords hardened by this procedure.

If you want the theory, here it goes:

What you should look for in a sword hamon is a crystalline aspect that shines especially when you examine it under the light – except for the cases where the sword has a special treatment.

Even if you don’t have it in your hand, you can easily tell from the pictures when the hamon is crystalline and when it looks engraved.

Some types of fake hamon can be really difficult to identify. However, this method will help you in most cases, because usually the fake reproductions are made with simple methods to lower costs.


Fake Hamon

Fake hamon katana

Real Hamon

Real hamon katana

Can you notice the slight differences in glow, transparency, and composition?


History of the Process

The tempering process has been used since ancient Japan to create strong and durable swords.

It began as a purely functional process. Little attention was paid to the hamon that emerged almost as a side effect.

With the passage of time, katanas and other samurai swords became more refined. Hamon design eventually became a central piece in the creation of swords.

Gradually, a paradigm shift changed the focus from the functionality of the tempering to the design of the hamon itself.

Although this did not guarantee an ideal distribution of the clay, hamon designs began to appear in the form of flowers, trees, islands, mountains, rivers, etc.

The hamon became a status symbol of the samurai. But also, a way for the blacksmith to express his own artistic sensibility.


The blacksmith manually forging the molten metal on the anvil in smithy with spark fireworks


Types of Hamon

Just as there are different types of art, there are also different types of hamon.

When distributing the clay, the swordmaker is responsible for giving the mixture special shapes. Still, it is important to set a good structure for the clay so as to not distribute it in a very uneven way. In this way, the hard and flexible steel balance properly at the end of the process.

Nowadays it is not usual to resort to such striking hamon lines as islands, trees, rat’s feet, etc. These types of designs could endanger the sword’s structure— making some of these peculiar designs would imply an ineffective distribution of the clay. However, it is possible to find a variety of attractive and functional designs.

Below are some of the most popular:


Hamon Notare (Wave Hamon)

This hamon pattern, as its name suggests, has an attractive shape reminiscent of waves. It is one of the most loved hamon types, both for its classic design and its harmonious aesthetics.

Katana hamon Notare


Hamon Gunome (Semicircular)

This is a semi-circular type of hamon that has medium sized wave patterns, similar to small mountains.

Gunome Hamon

Hamon Choji

The choji hamon has a catchy irregular design. Its pointed tips give the sword a wilder touch, which breaks with the conventional harmonic patterns of the hamon. It’s beauty in chaos.

Hamon Choji

Hamon Sugu (Straight)

This is one of the most humble hamon. No patterns or drawings; a straight and elegant line that starts at one end of the blade and ends at the other without deviating in the slightest.

Sugu Hamon



Polishing the Hamon

Sometimes, the hamon is polished to make it stand out and thus enhance the aesthetic values of the sword.

This process, hadori polishing, more than polishing itself it is a stage in the overall polishing process.

During this stage, the polisher uses hadori stones, which are a little more abrasive than normal. With them, he rubs the hamon area carefully, giving it a whitish appearance.

In this way, the line ends up contrasting more with the rest of the steel, standing out at first sight.

This aesthetic process is highly appreciated, and it has a variant called feather hadori.

What makes the feather hadori special is that, in addition to highlighting the hamon, it leaves a pattern of fine lines that seem to come off it and that resemble the feathers of a bird. That’s where its name comes from.



What about Popular Culture?— Jojo’s Bizarre Adventure

Being such an important part of Japanese history, the hamon has also found a place in popular culture.

One of the most recent cases is that of Jojo Bizarre Adventures. This is an anime in which, at first, the characters use their skills by channeling energy called hamon.

They controlled the hamon with the breath, so it was necessary the complete concentration of the character to use it.

Later, this hamon mechanics in Jojo is replaced with the stands. They are physical representations of this energy.

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