Wado-kaichin (can be called Wado-kaiho) was the coin minted and issued in Japan in 708. It was the first currency circulated in Japan. It was the first of the Kocho-Junisen (twelve coins minted in Japan).
The coin was a round shape with a diameter of about 24mm and had a square hole, 7mm on a side, in the center of the coin. Letters "Wado-kaichin" were written clockwise on the surface of the coin. No letters were written on the back of the coin. The format and calligraphic style of the coin was the same as those of Kaigen-tsuho, a coin issued in the Tang period in 621. The coin was designated as one Mon, the unit of currency set by the Ritsuryo government (an ancient Japanese government of centralized governance). It was said that one Mon could buy two kilograms of rice and was worth a day of work for an adult at the time.
In order to commemorate the discovery of Wado (a high purity copper which does not require any refining) in the Wado, presently known as Kuroya, Chichibu City, Saitama Prefecture, the name of the era was changed to "the Wado era" and also Wado-kaichin was created. Wado-kaichin was issued in order to establish the currency system like the one in the Tang Dynasty and also to cover the expenses used to move the capital to Heijo by the difference in the value between the bullion and currency value.
The Shoku Nihongi (Chronciles of Japan, continued) mentioned that Wado-kaichin, made of silver, were issued in May 708, the minting of the copper Wado-kaichin coins began in July of the same year, and the copper coins were issued in August of that same year. However, silver coins were discontinued in August of the following year. There were two types of Wado-kaichin; "Kowado" coins, which were thick and poorly made, and "Shinwado" coins, which were thin and made precisely. Shinwado coins are thought to have been issued after the silver coins were discontinued since only the copper Shinwado coins could be found. One theory explains that Kowado coins were issued in the early Wado-kaichin currency period and the other theory says that Kowado coins were issued as Shichusen (counterfeit money) or as trial coins before Wado-kaichin was officially issued. The composition of Kowado coins was different from that of Shinwado coins, as Kowado coins were made of almost pure copper. Furthermore, their calligraphic styles were also different from each other. Kowado coins did not circulate in large quantities and the number that were excavated was limited; on the other hand, Shinwado coins were circulated in a large quantity, and many Shinwado coins have been excavated. A large number of Wado-sen Coins traded now for ancient coin collections are counterfeit; therefore, cautions have to be taken.
Bartering with rice and cloths as standards was still the main method of obtaining necessary materials at the time in Japan; therefore, Wado-kaichin did not circulate as the currency well in Japan except in the Kinai region and its surrounding area. Moreover, there is a belief that it was difficult to secure a large amount of raw copper for minting coins at the time as the discovery of only one copper mine became a national event; furthermore, there is an opinion that the amount of coins circulated was not much. Wado-kaichin coins were used as a treasure to symbolize the wealth and the power in the country. Wado-kaichin coins were discovered all over Japan and even in ruins oversea such as a ruin in Bohai (a kingdom in Manchuria and North korea, established after the fall of Goguryeo).
Chikusen-joirei (an ordinance to ordain a court rank to someone who saved a certain amount of money) was issued in 711 in order to promote the circulation of the currency. This ordinance, targeted people who were lower than Jurokui (Junior Sixth Rank), announced that people who saved more than 10 kan (10,000 coins) would be promoted by one rank and two ranks for people who saved more than 20 kan. However, promoting the distrubution of coins and encouraging chikusen (saving a certain amount of money) were contradicting each other and Chikusen-joirei was abolished in 800 since it caused the storing away of coins.
The value of the coin determined by the government was significantly higher than the value of the bullion; therefore, the rampacy of Shichusen issued by civilians without permission from the government and declining of the currency value occurred. On the other hand, Ritsuryo government severely punished the minting of Shichusen as soon as Chikusen-joirei was issued; furthermore, the government anounced that ringleaders would be executed, accessories would be confiscated, and their families would be deported. However, large quantities of Shichusen circulated and the currency value decreased. Mannen-tsuho coins were issued in 760 and the value of a Mannen-tsuho coin was determined to be the same as 10 Wado-kaichin coins. However, the confusion continued when people were repaying their debts since Wado-kaichin and Mannen-tsuho coins had a diffferent value even though they had almost the same shape and the same weight. After the issue of the Jingu-kaiho coin, all three types of coins, Wado-kaichin, Mannen-tsuho, and Jingu-kaiho, were determined to have an equal value in 779 and they were all together used as the currency thereafter.
Wado-kaichin contained a letter "chin" which was thought to be a variant and a simplified character of "ho"; therefore, the letter "ho" was consistently used for coins which were officially minted thereafter. Therefore, Wado-kaiho was the main way to read. Contradicting to this theory, there was a different theory that "chin" was a variant character of "chin" (rare) and Wado-kaichin was read as Wado-kaichin causing a dispute for over 150 years since the Edo period. In recent years, "Wado-kaichin" theory is becoming predominant. Moreover, the following article was written in 683 (12th year of the Emperor Tenmu) in the "Nihonshoki" (Chronicles of Japan). "Copper coins had to be used from now on and; thus, the use of silver coins would be forbidden." Therefore, letters "Wado" written on Wado-kaichin had no relationship with "Wado" (Japanese copper) used as the name of the era. The theory, Wado-kaichin coins were issued all the way back in the era of Emperor Tenmu, was pretty much denied due to the discovery of a large amount of Fuhonsen coins, mentioned later.
Coins issued before Wado-kaichin included the Mumonginsen Coin and the Fuhonsen Coin. A large quantity of Fuhonsen coins were discovered in Asuka-mura, Nara Prefecture in January 19, 1999; therefore, the reports, the established theory that Wado-kaichin was the oldest coin would be overturned and textbooks would be rewritten, came out. However, it is thought that Fuhonsen coins were not circulated widely; furthermore, there is doubt if the coins were actually circulated as currency. Presently, Wado-kaichin was accepted as the oldest coin widely and certainly circulated as currency.