The Hamon: What, Where, Why and How

To those who appreciate the tempered steel of a Japanese sword, the hamon is visual evidence of the maker’s effort to produce the finest blade work. In the West, the hamon appears in much the same fashion on Western knives, a blending of culture and craft. Where East meets West on the steel blade, there is the hamon, the graceful temper line.

“From a practical point of view, the hamon is a visible indication of a differentially heat-treated blade,” explained knifemaker Stuart Branson. “In many cases, it’s advantageous to have a harder edge supported by a softer spine in a knife. In this way, you gain the benefits of the good edge retention afforded by the harder edge with the durability of the softer spine region of the blade. In the long and graceful form of the Japanese sword this might seem obvious, but the same is true for Western blades, particularly those hard-use knives or the very popular larger chopping knives.”

According to veteran maker Gary House, the aesthetic effect of the hamon is behind its surge in demand among Western collectors, clearly defining the transition zone between hard edge and soft back.

“The popularity of the hamon on non-Japanese blades today, I believe, is the visual effect of the temper line,” he commented. “The movement and variations of the hamon are very attractive and visually appealing compared to a straight temper line.”

More and more, discriminating knife customers are looking for the hamon on the blades of some of the best-known, iconic Western-style knives.

“‘You will put a little something in the blade, won’t you?’ is a common request these days,” commented Mike Craddock, who started making knives in the 1970s, took a 40-year hiatus, and has come back strong recently. “It doesn’t necessarily make the knife better, but it does look good. I consider it the spirit of the steel.”

Certainly, the hammered and heat-treated steel is expected to be sturdy. However, the quest for the hamon is a classic case of discovering what lies beneath.

“For me, it is the mystery of the hamon,” related bladesmith Erik Fritz. “What shape is it going to take? How much work is it going to entail to bring it out so it can be seen? I think what makes it so special is that each hamon is so different and unique.”

 

PRODUCING THE HAMON

The hamon is there, lying within the reach of the knifemaker who is willing to take the time to thoroughly rub the steel to enhance the elusive line. For some makers, that effort is standard procedure. To them, a blade without this unmistakable flair of the Orient just comes up short. A hamon on Western knives bridges cultures and demonstrates a willingness on the maker’s part to invest the time and energy required.

“Like many, I have always been enamored of the Japanese sword,” Branson said. “The hamon is integral to its design and construction, and although it isn’t necessary that it be brought out to that degree, polishing these swords has been elevated to an art.”

Branson says he attempts to achieve several goals in the production of the hamon. First, he wants to emulate the beauty of the Japanese blade. In the attempt, he learns to see the intricacies of the pattern, theory of design, and the dedication of the artists that have gone before him.

“Producing a hamon is not just adding clay to a blade and hoping for the best,” he reasoned. “It is understanding the steel being used, the temperatures and times needed to achieve your aim, and the amount and pattern of the clay to produce the hamon you are after, the delicate process of heating the blade properly before the quench and, in the case of water quenching Japanese-style blades, the terror and elation of a successful water quench—the violent transformation of the steel into two forms above and below the hamon line, and the resulting curvature induced. One can understand how the swordsmiths approached their craft with a religious reverence.”

 

WATER VS. OIL QUENCH

Producing the hamon involves a process of coating the blade with clay and then quenching it in either oil or water. The water quench is more rapid and therefore potentially more catastrophic should a crack or complete break occur.

“I use clay and white crushed stone,” House noted. “A paste of satanite also works well. The clay insulates the blade from heat and will be a thin layer as it comes down toward the edge of the blade.”

Most makers who frequently produce a hamon opt for such tool steels as W1 and W2, and carbon steels such as 1050, 1075, 1084 and 1095. “Simple carbon steels are conducive to the very fast quenching requirements of a clay-coated quench,” Fritz remarked. “This allows the insulating clay to retard the hardening of the coated areas of the blade. High-alloy steels that allow thorough hardening of the blade are not conducive to the creation of a very active hamon. What you get with the high-alloy steels is more of a straight line.

“With W2 I prefer the water quench,” Erik continued. “With 1084 and 1095 I use Parks 50 quenching oil. Any hamon requires an insulating layer of clay to be applied to the spine. The biggest difference in hamon activity is in the quenching medium, such as water or oil. In my experience and opinion, greater hamon activity is achieved through a water quench. If you are going the safe route and using oil, there is less chance of a catastrophic blade failure.”

Branson said he sees fundamental differences in the hamons produced and the effects of the water or oil quench on the steel itself. On Japanese-style blades, the water quench introduces sori, or curvature to the blade. As the water quenches the steel, the uncoated steel cools quickly while the coated spine retains heat, staying expanded longer and causing the blade to curve downward. As the spine cools, the hardened edge begins to curve upward.  Quenching oils are typically made for industrial use and to prevent deformation of the steel as much as possible. Consequently, the blade tends to curve downward and remain so.

When quenching a blade in water, Stuart added, “The hamon tends to be more cloudlike, more diffuse, and to my mind a little more mysterious and poetic. The oil hamon, however, is more literal, more willing to follow the clay pattern and is more defined on its boundaries. However, the ashi, the wispy lines that come off the main patterns, can be very delicate and defined. Control of this can make for a very exciting hamon.”

The investment of both materials and a significant amount of time impact the cost of a blade complete with a hamon. However, for the maker willing to commit the time and the potential buyer, a genuine value is readily apparent.

“You do have extra work in claying the blade,” Craddock said, “and then there are literally hours of hand rubbing to get the aesthetics right. The steel does what it wants to, but there is a process that you go through. The steel offers it if you are willing to go out and get it. To me, the time involved in the hamon, and about 90 percent of the steel blades I make have them, adds about 10 percent to the cost of the knife—but from the standpoint of hours it should probably be double.”

 

LANGUAGE OF THE BLADE

The hamon brings beauty and satisfaction to the maker and the buyer. Further, it is taking its place among the desired aesthetic effects of Western knives, proving that the world is indeed much smaller when the same language is spoken—in this case, the language of the blade.—BY MIKE HASKEW

What To Look For in a Hamon

 

Discriminating knife buyers looking for a quality hamon should bear a few things in mind. A hamon can be wavy, undulating or any number of shapes. Whatever the shape, it must be well formed, clear and unbroken. What’s more, according to Don Fogg, it must be possible to describe in an understandable manner using a traditional vocabulary.

Erik Fritz advises that a professionally done hamon will exhibit a sharp demarcation between the hard and soft areas. Watch out for a hamon line that dips too close to the cutting edge. Stuart Branson agrees that if the hamon comes close to or reaches the edge of the blade, then a section of the edge is not hardened properly. Levels of refinement in the hamon involve subjective preferences as they relate to clarity and detail.—BY MIKE HASKEW

 

 

How To Obtain a Hamon

 

For more on producing a hamon, see “How To Clay Temper and Obtain a Beautiful Hamon” by ABS master smith Don Fogg in the book, Spirit of the Sword. To order a copy call 1-855-278-0406 or visit www.shopblade.com and click on “Books & References.”

CAPTION FOR PICTURE AT TOP

For his stag “Ferncliff” model, Lin Rhea employs a wavy, cloud-like hamon on the 9-inch W2 tool steel blade. Overall length: 14 inches. (Chuck Ward photo)

 

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