「Yukichika」 The Genius "Daiya" - Japanese Woodworking Plane Body Artisans

A brief background on the birth of Daiya

Daiya, a profession that appeared in Japan during the Meiji era ( Lasted from 1868.10.23 to 1912.7.30), specializes in making woodworking plane bodies.

Daiya is divided into two types, one that mainly makes wood bodies mainly for flat planes, and the other that makes more complex special plane bodies. This kind of Daiya is called "Kusemono" Daiya(くせもの台屋).

Several planes made by Kusemono Daiya in my collection.

Before the Meiji era, the body of the plane and the wooden handle of the tool were made by the user himself. In other words, from the perspective of the division of labor in traditional Japanese society, the only profession that made tools before the Meiji era was blacksmiths. Saws were an exception, and professional sawsmiths appeared as early as the Edo era.

Since the Meiji era, the traditional simple wooden plane consisting of a wooden body and a blade has absorbed elements from Western tools, and the number of components of the plane has increased. For example, the Japanese flat plane with a chip breaker that became popular in the second half of the Meiji era, which absorbed the concept of the chip breaker in the European plane, has changed from a simple blade + wooden body to a four-part plane: blade + chip breaker + wooden body + metal rod.

The various planes in this book only have blades with wooden bodies

『和漢船用集/Collection for Japanese and Chinese ships, 1761』

Compared with the traditional simpler plane, this new type of plane has higher requirements for manufacturing precision. As Japan's modernization process accelerates, cities expand, and industry and commerce prosper, the growing carpenter practitioners in the city have a surge in demand for various types of planers. It is obvious that tool trading companies can no longer meet the actual demand of the current market by only providing blades and chip breaker. These stores began to recruit full-time workers to make plane bodies, and make simple or complete adjustments and sharpening, providing customers with planes that can be used directly or with simple adjustments.

The protagonist of this blog is a representative Daiya cultivated in a tool shop in Tokyo under this background.

Apprenticeship Period

In the early Taisho era (Lasted from 1912.07.30 to1926.12.25) of Japan, the son of a blacksmith named Aigami Choukichi (相上長吉) became an apprentice at the tool shop Tokubei Shoten in Yotsuya, Tokyo, after graduating from elementary school, where he learned how to make various types of plan bodies. 

Aigami Choukichi who was called a genius artisans by Tsuchida Noboru, quickly distinguished himself during his apprenticeship. He quickly mastered the production technology of special plane bodies (Kusemono), which are more complicated than common plane bodies, and he also devoted himself to developing and improving existing products.

The most representative one is the chamfering plane carriage that can be adjusted only by wood screws. The old adjustable chamfering plane (角ダボの面枠) uses a wooden strip structure to connect the carriage and play an adjustment role. Since the Meiji era, metal screw structure carriages have appeared (micro-adjustable, more convenient than the old ones). However, some "conservative" Japanese carpenters feel that the metal structure from the West destroys the harmony of this plane.

 Wood Strip Adjustable Chamfering Plane(角ダボの面枠) , these two was exhibited at the Takenaka Carpenter's Tool Museum from March to May this year. Currently in the collection of the tsuchida store in Sangenjaya, Tokyo.

Therefore, Aigami Choukichi tried to redesign and develop an adjustable chamfering plane with a wood screw structure. In Japan at the beginning of the last century, Aigami   Choukichi had to solve three difficulties when making a wood screw chamfering plane:

1. Taps and dies for making internal and external threads were rare tools that could only be imported from the West at high prices in Japan at that time, he could only make them himself.
2. The opening and closing speed of the plane carriage cannot be too slow, it is necessary to find a thread of the right size.
3. The plane carriage is often opened and closed, it is necessary to make a suitable thread shape to reduce wear during use.

He solved the above problems with little effort and successfully launched an adjustable chamfering plane that can be opened and fixed with wood screws. He also designed a set of processing tools for mass production of this plane. This plane was a great success and achieved huge sales.

 Wood Screw Adjustable Chamfering Plane by Aigami Choukichi 『Yukichika/行近』, this plane was exhibited at the Takenaka Carpenter's Tool Museum from March to May this year. Currently in the collection of the tsuchida store in Sangenjaya, Tokyo.

Detail of the threads of a wood screw adjustable chamfering plane.

At this time, although few carpenters in Tokyo knew about Aigami Choukichi, they all knew that there was a "genius Daiya Artisans" in Tokubei store. As a result, Tokubei store successfully became one of the famous carpentry tool stores in Tokyo.

※The owner of Tokubei Shoten at that time was Kato Tokusaburo. After Tokubei Shoten completed the initial accumulation of capital as a tool store, it transformed itself and gradually gave up the woodworking tool business.

※For more information about adjustable chamfer plane, please refer to this blog: https://covingtonandsons.com/2024/06/15/japanese-handplanes-the-adjustable-chamfer-plane/

Become an independent Daiya

In 1924 or 1925, after paying the penalty to Tokubei store,  Aigami Choukichi terminated the "Houkou/奉公" contract early and began to make plane bodies independently under the brand name "行近/Yukichika".

※ Houkou/奉公: It is a tradition in East Asia that after an apprentice enters a shop or a craftsman, he or she usually has to work for free for a few years as a thank you, which is called “ Houkou/奉公”. During the apprenticeship and Houkou stages, the master or shop is responsible for food, clothing, housing and transportation.

According to Yukichika himself the reason he left Tokubei Shoten early was not because of any unpleasantness with the store. The direct reason was that a fellow apprentice named Ikegami would suddenly have "epilepsy" at work, accompanied by violent vandalism, which disturbed he so much that he left the store several months before his "service" was completed.

Usually, when a craftsman first establishes his own brand, he has to go through a relatively difficult "start-up period", but Aigami Choukichi is an exception. One reason is that the adjustable chamfering plane for wood screws that he developed during his apprenticeship was something that no one else could make except him. The second reason is that before he became independent, the various special planes that he made and sold under the brand of the Tokubei store had become popular products in the Tokyo.

For example, the high-precision Kikai Shakuri Kanna that can be used directly.

The history of Kikai Shakuri Kanna(Japanese plough planes) is not long. Naohei store, the oldest tool shop in Hatchobori Tokyo, installed a movable fence on the basis of the traditional plough plane in 1906. Later, a more convenient metal screw structure was used to connect the fence and the plane, and the left and right blades in front of the main blade (to cut the fibers at the edge of the groove ahead of the main blade) and a chip breaker were added to improve it.

At that time, Naohira Shoten named this plane "改良溝鉋/Improved Plough Plane" and obtained a patent, which was a big hit. Although this complex new plane improved work efficiency, its precision processing capability was limited and it was difficult to adjust. 

Kikai Shakuri Kanna from Naohei store in my collection.

This plane was also used to process the grooves for installing glass in wooden doors and windows at the time. As the thickness specifications of industrial glass became more and more precise, the store had to adapt to this trend and produce more precise “ Kikai Shakuri Kanna”. The precision error of the processed groove width could not exceed 0.1mm, such as 2.1mm, 2.3mm, 2.7mm, 3.0mm, 3.3mm and other specifications. Even the highly specialized special plane bodies artisans at that time found it difficult to achieve the above accuracy.

At the end of the Taisho era, the patent period of Naohira store's "Improved Plough Plane" expired, and Tokubei store launched a high-precision and directly usable “ Kikai Shakuri  Kanna”. Of course, there was no other plane bodies artisans in Japan who could produce the above precision except Aigami Choukichi, that is "Yukichika" after independence.

Wood Screw Adjustable Kikai Shakuri Kanna by Aigami Choukichi 『Yukichika/行近』, this plane was exhibited at the Takenaka Carpenter's Tool Museum from March to May this year. Currently in the collection of the tsuchida store in Sangenjaya, Tokyo.

It is difficult to produce such a high-precision and ready-to-use complex plane body using traditional hand tools. In terms of measuring tools, Aigami Choukichi used precision calipers and micrometers instead of traditional Sashigane (Japanese carpenter's square); he used imported precision electric tools that were expensive at the time to improve processing accuracy. For example, he transformed a precision grinder with very small vibration amplitude produced by the Swedish company SFK (Svenska Kullagerfabriken) into a lathe; he used an American bench drill that ordinary artisans at the time could not afford. These tools accompanied Aigami Choukichi throughout his nearly 60-year career. The above-mentioned Swedish and American tools are collected by the Tsuchida store, and the bench drill is on the left side of the store entrance.

※ According to Tsuchida's records, Ikegami was probably jealous of Aigami Choukichi, which led to negative emotions and psychological problems and violent tendencies. This man named Ikegami was a relative of a chisel blacksmith in Tokyo. After completing his "service", he returned to his hometown in Niigata and became an ordinary Kikai Shakuri Kanna bodies worker. 

Work during World War II

During World War II, Japan was in a very short supply of productivity, and the production of woodworking tools was not allowed by the authorities. Aigami Choukichi was sent to a military factory near Shinjuku to make screws (without salary). While working at the military factory, he transformed the production line that originally required manual participation into a fully automated production line, greatly improving production efficiency and product precision. As a result, he was discovered by the factory leader and sent to work in the studio of Dr. Hideo Itokawa of Tokyo Imperial University. Aigami Choukichi's main job was to make three-dimensional wooden models (mainly curved surface parts on aircraft) based on plane design drawings.

Aigami Choukichi and Tsuchida Ichiro talked about this work many years later. Aigami Choukichi said: "Making these wooden models is much easier than making chamfer planes. Usually I get the design drawings from Dr. Itokawa Hideo, and he will give me about a week to process them, but most of them I can finish within a day. Dr. Itokawa Hideo also paid me a salary from the research funds. The work at that time was the most profitable time for me.”

After Japan's defeat, Itokawa Hideo invited Aigami Choukichi to go with him as his assistant before going to the United States, but Aigami Choukichi refused. His reason was "I'm scared of flying on airplanes.”

An honest and open-minded “Geek"

From Tsuchida Noboru's writings and related materials, as well as my communication with Tsuchida Noboru, I learned that Aigami Choukichi was a workaholic with almost no hobbies or bad habits, with an innovative spirit, working from morning till night, with almost no days off. In today's terms, he was a technical geek in the field of plane bodies at the time. He rarely chats or expresses his opinions, as all his ideas are integrated into his products. But if you are also an expert and ask questions about related technologies, he will teach you everything he knows without reservation, which is completely different from the traditional artisans who keep their own technology secret.

When he was about to retire in his later years, he gave a set of production tools he designed and made to produce wood screw adjustable chamfering planes to Toda Yasuo, the best "Kusemono" Daiya at the time, through the Asakusa Suiheiya store.

At first, I thought Toda Yasuo was the apprentice of Aigami Choukichi, but Aigami Choukichi did not have an apprentice in his life. He may have simply believed that good production tools should be handed over to skilled artisans to continue to be used, regardless of whether he is his apprentice or he has never met.

Later, the Daiya Toda Yasuo, who did not have his own brand, did not disappoint everyone. He used this set of tools to produce a product that was almost the same as the wood screws adjustable chamfering plane made by Aigami Choukichi, and it was also well received by carpenters.

A wood screws adjustable chamfering plane by Toda Yasuo from Suiheya store in my collection.

The other side of the "perfect" product

Aigami Choukichi has raised his professional ability to a level that is difficult for ordinary Kusemono Daiya to reach with his talent and hard work. The Kikai Shakuri Kanna and chamfering planes he made, set up and sharpened provided great convenience for carpenters' work. Carpenters could buy these planes and bring them to the site to work immediately, which saved the carpenters a lot of time to make bodies, set up and sharpen these complex planes.

But the reality is that no matter how "perfect" a plane is, it will need to be sharpened and re-adjusted by the user after a few uses. If the carpenter using these planes is not skilled in sharpening or setting, the "perfect" tool that works very well shortly after purchase will have its "performance" drop off precipitously after sharpening and adjustment. For this reason, there was a saying circulating in the market at that time that "these special planes (mainly Kikai Shakuri Kanna and special chamfering planes) perform best when they are first purchased.”

A Bozu-men Mentori kanna(Monk's head chamfer plane) from a retired carpenter in my collection.

This rumor confirms the technical achievement of Aigami Choukichi, the highly specialized representative of Kusemono Daiya. On the other hand, it also reveals a trend that with the industrial division of labor in woodworking tools, professional artisans have reached an unprecedented level of technical achievement, providing the market with a large number of woodworking tools with stable quality and even ready for direct use. At the same time, the ability of carpenters to adjust the woodworking tools they purchased is declining compared to carpenters before modernization.

The End of Kusemono Daiya

With the popularity of power tools after World War II, the survival space of Kusemono Daiya shrank rapidly. The highly acclaimed and popular precision Kikai Shakuri Kanna were replaced by electric wood groove cutter , and various chamfering planes were replaced by laminate trimmer and wood routers. According to Tsuchida Noboru's records, by around 1980, it was almost impossible to see carpenters using chamfering planes and Kikai Shakuri Kanna.

The profession of Kusemono Daiya has not disappeared quickly. It is just that as the demand for tools for woodworkers naturally tilted towards electric tools, which prompted electric tools to develop in the direction of more functions, more precise processing, more convenient use, and even intelligentization, Kusemono Daiya lost the soil for its development and could only withdraw from the stage under the trend of the times and provide some simple products that are still needed by carpenters in order to make a living. For example, small or mini planes, rabbet planes, standing blade planes, ordinary groove planes, marking gauges, and also the wood screw adjustable chamfering plane developed by Aigami Choukichi, etc.

A standing blade plane by Yukichika from Suiheya store in my collection. This was made in his later years.

As far as I know, the exact time when the Kusemono Daiya profession disappeared should be the end of September 2011, when the Kusemono Daiya in Sanjo area retired with the brand name Kinshiro. Compared with the blacksmith profession of plane blades, chisels and saws, which has existed for thousands of years in the woodworking tool industry, the 100 years of appearance and farewell of Kusemono Daiya with high technical level such as Aigami Choukichi, Toda Yasuo, Tobei and Kinshiro in Sanjo area is just a glimpse in the long river of history. In the future, the Kusemono Daiya profession is unlikely to appear again, but the big tree planted by the efforts and innovations of these plane body making artisans, especially Aigami Choukichi, has already produced many achievement, waiting for the later generations to pick them.

A standing blade plane &  a rabbet plane by Tobei from Naohei store in my collection. Some shop owners told me that his works were more expensive than Kinshiro's at that time. Naohei shops still sell his Hira Kanna, but the blade smith is unknown.

 

Reference:

• Tsuchida noboru 土田昇, 『職人の近代 - 道具鍛冶千代鶴是秀の変容 Modern Artisans - The Transformation of Toolsmith Chiyotsuru Korehide』，2017.

• 『 鉋台をつくる ー東京における台屋の成立と発展 Crafting the Kanna-Dai : The Formation and Evolution of Plane Body Artisans in Tokyo』, 2024.

• 船曳 悦子 Etsuko FUNABIKI, 『近現代における鲍の変遷について Historical Changes of the Plane in the Modern Era』, 岐阜市立女子短期大学研究紀要第 60 輯(平成 23 年3 月), Gifu City Women's Junior College Research Minutes No. 60 (March 2011)

• 金沢兼光 Kanazawa Kanemitsu,『和漢船用集/Collection for Japanese and Chinese ships』1761