TOYOKUNI – A Japanese knife employing Katana technology


The real meaning of ‘Strike while the iron is hot.


Makoto Hamaguchi said in 2003, “I must hammer the metal six times to finish up the material shape, while my father or brother can make it as they like in three times.” In 2016, he stands at the working site of Toyokuni, and just about to complete the hammering process in three times. And, yes, he has done it no more than three times. Now he is a smith who can be proud of his speed of the finishing work as fast as his father. “It took me forty years to catch up with my father.”


He was copying the work of the smith since four years old, playing around the corner of the factory his father owns. He was assigned to do the simple tasks, such as varnishing, when he turned six years old. “I started part-time job for sweets!” Makoto says with laughing now, but the task he was assigned was too far to call a play for kids. He recalls his youngest career, “My father taught me how to hammer material, sharpen a knife, and move the body as a forger.


A steel and iron will be adhered firmly after applying boric and solution.

A steel and iron will be adhered firmly after applying boric and solution.


A hammer hits the steel glittering in red, which is just drawn out of yellowish white flame with 1100 degrees. The forger hammers the steel plate weakly in the beginning for several times. The ash falls down like a thin film from the surface of burnt steel, which are impurities included in material, such as carbons. The steel becomes soften if its purity is high. “When you want to make it harder, you need a certain amount of impurities remained”, Makoto explained and added that a forger must be able to figure out that amount by sensing it through his hand. Also, he gives strong hits on steel immediately after the weak hits, saying “The most important factors are preparation and response for forging”. If someone hammers less number of times than the others, he understands how the steel transforms in next process and can react with it by hammering the material in the best required timing. “My arms sense the state of the steel through the reaction transmitted from materials. I am talking to the steel though the medium of my hand.” He believes that in his younger days he might have not had this communication technique with steels as much as his father or brother had. I reckon that now he hardly loses a word in the conversation with steels.


A word ‘forging’ in Japanese is constituted of a letter meaning ‘to anneal’ (鍛) and another letter meaning ‘to make’ (造). Steel or iron cannot be just hammered and conquered, but can be annealed.


The knife shape starts to appear after being forged.

Left: The knife shape starts to appear after being forged.

Right: The material will be matured for approximately twenty years as iron and steel attached


We have a saying in Japan, “Strike while the iron is hot”. This would practically mean ‘You must remember to form something before it gets consolidated.’ We often cite this phrase as an example of instruction policy for young people in growing stage. It’s often too late to build up something once you confirmed as it starts getting formed. “Strike while the iron is hot”—-The saying does not suggest that you should form everything in one die to make copies. No conquers, no controls will be needed, on the contrary you must see what kind of state will be likely to be grown in next process, and then have a conversation with the object.


We need here an ability to sense the stage. The letter “anneal” (鍛) is constituted of the ‘metal’ (金) part on the left side and the ‘step’ (段) part on the right side of the structure. To sum up, you must foresee which stage the metal having been heated and transformed will be moves to. This is meant to be “anneal” (鍛) literally. Both a human being and metal processing cannot go back once it’s developed.


Neither metal processing nor human development can go back.

Neither metal processing nor human development can go back.


Soudou Kawaguchi, a photographer, was shooting the work of Makoto Hamaguchi. A photographer often asks the model for posing and Mr. Kawaguchi wasn’t exception. Especially human portraits require such posing requested as a matter of course. While he was holding his camera, the word just escaped from Soudou’s mouth. “Oh, I just missed it…” I believe, it was just a moment when Makoto Hamaguchi lifted up the hatchet heated in red from the furnace. “It’s impossible.’ Makoto shortly replied, pouring boric acid on the heated hatchet, and then he put it back to the flame. It might have taken just a second or even less. The photographer wanted to take a photo of that posture thus he naturally opened his mouth. However Makoto could not stop moving even for one second, because he realized that the transformation of the steel had been occurring and did not allow him to go back to the former process. So he made up his mind to move onto the next process.


I was misunderstanding the meaning of the saying, “Strike while the iron is hot”. This does not mean ‘observe it first, and then hammer it’, but the true meaning of the words should be interrupted as ‘a trainer (forger) must be responsible to face the person or the object with whole in mind and body together, where he follows the flow of its transformation.’



Left: 1100 degrees furnace

Right: Driving a wedge into a hot blade


I did not ask any questions while Makoto’s whole body was moving, or anyway I couldn’t do it. He kept on moving like a Samurai who faces a battle without saying any words. The shape of the blade begun to appear vaguely, and then Makoto’s hand was sharpening the knife as well as polishing it. Then, I suddenly realized, “It’s flowing!”


The way Makoto using his body is similar to a master of the martial arts. His back is straight while he walks with the shortest steps, breathing deeply, and his hands moves without any useless shit till to the fingertips. He is following the flow of the work, time, and the metal transformed. Japanese martial arts, especially Kendo, the Japanese fencing, emphasize the flow thus Japanese sword, Katana, is never controlled against the flow. We have the word ‘the school of flow’ (Ryu-ha) in Japanese to categorize the schools of martial arts, such as Shinto-munen ryu, Hokushin-ittou ryu, Jiki-shin-kage ryu, Kurama ryu, Onoha-ittou ryu, shool, and Jigen ryu. There are so many Ryu-ha of martial arts born in this country through any eras and lands, all of which named their schools after ‘ryu (流)’, referring to their way of swordplay. It was pretty natural for them to categorize themselves using the word flow rather than type or class.


Makoto instructs a disciple as “strike while the iron is hot.”

Makoto instructs a disciple as “strike while the iron is hot.”


Makoto Hamguchi at Toyokuni performs his work in the flaw of forging various knives. And this may not be a coincidence that he reflects the Japanese spirits in his own manufacturing as a successor of Katana forger today.



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