The Sen That Was Never Issued

From the 13th year of the Shōwa era (1938), the quality of coinage materials began to decline. Silver and cupronickel disappeared, replaced by aluminum.

The one-sen aluminum coin issued in Shōwa 16 (1941) had a diameter of 16 mm and a weight of 0.65 grams. Until the previous year, it had been 17.5 mm and 0.9 grams. By late Shōwa 18 (1943), it was reduced to 0.55 grams.

The Hand Knows First

The ten-sen aluminum coin, too, had its weight reduced twice from one and a half grams to just one gram. In Shōwa 19 (1944), coins made of tin and zinc appeared. With transport from the occupied southern islands cut off, tin was the last remaining option.

The Metal Recovery Act of Shōwa 16 (1941) took temple bells, as well as pots and pans from homes.

The one-sen coin in your palm grew lighter year by year. Even without reading the numbers, the hand knew first.

Kilns for Tea Bowls Fire Coins

By Shōwa 20 (1945), metals were exhausted. The government then decided to make coins from clay. These were ceramic coins. One sen, five sen, and ten sen. The plan was for 500 million each of the ten- and five-sen coins, and 700 million of the one-sen coins.

Shōfū Kōgyō in Kyoto, Seto, and Arita. Kilns that fired tea bowls now fired coins. The clay was a mixture of Mino clay with Izumiyama porcelain stone and red clay. What emerged from the kilns were small, reddish-brown discs. The one-sen ceramic coin was formed to a diameter of 15 mm.

About fifteen million pieces had been fired when the war ended.

Legally, They Never Became Money

These ceramic coins were never ultimately issued. Although they existed as physical objects and even reached mass production, legally they never once became money. The majority were discarded.

Here, the condition for a coin to be a coin is laid bare. It is not that it has been fired, nor that it bears a face value. It is the single point of whether or not it has been issued.

In the 3rd year of the Reiwa era (2021), news spread that about 500,000 pieces had been found in a warehouse of Shōfū Kōgyō. The clay that was supposed to become money had been sleeping as mere lumps of earth.

The One-Yen Coin, Ten Years Later

In June of Shōwa 30 (1955), the one-yen aluminum coin was issued. Pure aluminum, 20 mm in diameter, weighing one gram.

For the first time after the war, its design was chosen through a public competition. From over 2,500 entries, the sapling on the obverse by Masami Nakamura and the "1" on the reverse by Tokio Takashima were selected. The lines drawn by unknown citizens became the design of the nation's currency.

It was the same aluminum. The metal that had been continuously debased now returned, bearing a design chosen by the public.