High temperatures are required to reduce iron sand and iron ore and obtain iron when using charcoal. The ingredients can be reduced even at temperatures under 1,000°C, but it takes an extremely long time. Moreover, the iron obtained is spongy, and if it is not heated again to a half-melted state forging will be difficult. To efficiently obtain iron requires putting the iron source in a reducing environment, and maintaining the temperature at the melting point of iron sand (approximately 1,400°C) for a long period of time. This is why the bellows, or fuigo, are indispensable as a tool for generating wind.

The first bellows to appear in any of Japan's written histories are the ama-no-habuki bellows made from a leather sack, recorded in the Nihongi. These bellows were made by skinning the hide of a deer. It is thought that bellows of this sort originated in China and were brought to Japan via the Korean Peninsula. Reliefs of leather bellows have been found carved hanging above Han Dynasty objects excavated in China. A late Han document reveals that iron was obtained and farm implements made using bellows that were operated by a water wheel.

Leather bellows (depiction of iron manufacturing care of the Kobayashi family, Iwate Prefecture) (source: A Guide to the Wako Museum)

An air-pumping pipe, or tuyere, thought to date to the 2nd or 1st century B.C.E., was found in the ruins of a blacksmith's house in Gyeonggi Province, South Korea. It is believed that in the earliest era of iron-making, small furnaces would be built in drafty places such as mountain valleys, and the iron would be made using natural ventilation. However, in Japan it was unusual to find a large tuyere that assumed the use of natural breezes. Most furnaces used bellows. Perhaps these were leather bellows along the lines of the ama-no-habuki.

According to Japan's oldest dictionary of Chinese characters, the Wamyo ruijusho of 930 C.E., the native Japanese reading of the Chinese character for bellows is fukikawa. Over time, the pronunciation changed to become fuigo. It may well be that the bellows came to Japan at the same time as metallurgical technology. The same early dictionary also has another entry for the same two characters, read as tatara (“foot bellows,” see section 1). It is believed that the foot bellows were developed for use in iron manufacturing because the leather bellows were too weak and inadequate for fabricating a metal with a high melting point like iron.

Foot bellows (tatara) (from Nihon sankai meibutsu zue [Illustrations of notable things from around Japan] [1754]) (SOURCE: A Guide to the Wako Museum)

Einosuke Murakami, a researcher interested in the history of steel manufacturing in Japan, notes that one can see two paths for the development of bellows around the world. One he describes as that of the saucer-style bellows found in the southern culture regions, including the ancient Orient and India. The other is the leather bellows found in the ancient northern cultural sphere. The Zhongyuan region of China is part of this latter group. The pump bellows was developed in the cultural border-crossing zone that stretches from this area in southern China to the Indochina Peninsula, a development that incorporated elements of bamboo tool-making culture into the leather bellows. This, it is hypothesized, may have been a step on the road to the development of the fukisashi bellows. In Japan, the bellows used for iron manufacturing in ancient times shifted over time from the leather bellows to the foot bellows, but by the medieval period it is the fukisashi bellows (a box-type air-pump) that become common. However, there were iron-manufacturing sites that continued to the foot bellows until early modern times, and the use of both foot bellows and fukisashi bellows persisted in iron-manufacturing use until the invention of the tenbin-fuigo at the end of the 17th century.

Fukisashi bellows (SOURCE: A Guide to the Wako Museum)

The early drawing of a tatara (ironworks) is taken from an 18th century work called the Nihon sankai meibutsu zue, roughly, “Illustrations of notable things from around Japan.” It shows six banko working the foot bellows. The plate-shaped main section of the bellows formed from hardened clay along the sides and bottom is partitioned into two sections along the center. There is a valve in each section for allowing air to be drawn in, and exhaust to be forced out. Planks called shima-ita, matching each section perfectly, are laid on top, and air is stirred by walking on the planks. The large oga saw, and a special kind of carpenter's plane called daiganna appeared in the Muromachi Period, which together made it possible to make large and long planks of wood. As a result, wood replaced clay for the main section of the bellows, which also increased the force of wind from the device. It is believed that these changes soon became widespread.

The fukisashi bellows is typical of the bellows known mainly as a blacksmith's tool. As the illustration shows, the structure was that of an airtight box. Special contrivances were fitted in the bottom of the box that helped to distribute the wind evenly, and ensured that wind would continue to come out whether the handle was pushed or pulled. It is not clear when the fukisashi first came to be used, but it is thought to have been after the 15th century, since wooden planks that could be made at low cost became more widely available some time in the first half of the Kamakura Period.

Fukisashi bellows were easily transported, even though they were large. The ability to generate wind could also be increased by linking two to four of the bellows together. Iron production increased rapidly with the appearance of the tenbin-fuigo, and the okaji and kokaji operations involved in the processing of iron became extremely busy. As a consequence, demand for fukisashi bellows intended for use by blacksmiths increased rapidly, and there developed certain locations known for producing them, such as Osaka Tenma (in the present-day city of Osaka). The shogunal government also established a special state-run iron market called the tetsuza, which operated in Osaka from 1700 to 1787. Iron wholesalers and brokerages came to be concentrated in Osaka, and iron mines and blacksmiths throughout the country became connected through the Osaka fuigo. People who used bellows included iron mine masters, metal casters and blacksmiths, along with barbers, makers of metallic ornaments, and tinkers at the gold, silver, and copper mines. Once a year, on the 8th day of the 11th month according to the old lunar calendar, people in all these professions would take part in the fuigo festival, a tradition that continues today.

A tenbin-fuigo (SOURCE: A Guide to the Wako Museum)

The tenbin-fuigo required significantly less labor for the banko who walk on the bellows, and rapidly increased tatara productivity. Its development is characteristic of the Chugoku region. The change was made from fukisashi to tenbin bellows in Hoki (located in western Tottori Prefecture) in the 1680s, in Izumo (Shimane) and Aki (Hiroshima) in the 1690s, and in Iwami (western Shimane) sometime between the 1710s and 1730s. The establishment of the takadono tatara (in short, a permanent, non-moving tatara) system accompanied this shift. The tenbin-fuigo doubled the efficiency of iron production over that possible with the fukisashi bellows (linking two together), and almost quadrupled that over that with the foot bellows. Temperatures also increased, establishing the early modern tatara iron-manufacturing techniques of zuku-oshi and kera-oshi.
As the illustration shows, the tenbin-fuigo is constructed by cutting a shima-ita plank such as that shown in the illustration of the foot bellows down the middle, dividing it into two parts. The axle at that fulcrum point is moved to both ends, to the front and back of the plank. Next, a kankan (a kind of crossbeam) is built to control the operations of the shima-ita on both the left and right sides of the apparatus. It is called a tenbin-fuigo, or “balanced bellows,” because when the shima-ita on one side is pressed down the shima-ita on the other side goes up. There are tenbin-fuigo operable by one person and others to be operated by two. Most of those used in the Meiji Period were for one person. Foot bellows and tenbin-fuigo were not much used in the Ou (Tohoku) district. Instead, they mainly used a type of large fukisashi bellows called the odenma.

Over time, fewer and fewer people were willing to become the banko who operated the bellows because of the harshness of the work, and waterwheels were used in their place to supply the motive force. Waterwheel bellows came to be used in the Chugoku region during the Meiji Period. The first waterwheel bellows to be used in Japan were those built in 1857 for the Western-style Ohashi blast furnace in Kamaishi, Iwate Prefecture, constructed by Oshima Takato. One wonders why it was that Japan was 1,900 years behind in the use of waterwheel bellows, when the Chinese were already using such devices during the Han dynasty.

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