The New Currency Act and the Five Old Gold Coins
The Meiji government enacted the New Currency Act in 1871 (Meiji 4). The units of money changed from ryō, bu and shu to yen, sen and rin. One yen equals 100 sen, or 1,000 rin. In law, the New Currency Act adopted a gold standard. It defined 1.5 g of gold as 1 yen (according to the Currency Museum). The gold coins issued under this act are the five types now called the "old gold coins." Their denominations are 20 yen, 10 yen, 5 yen, 2 yen and 1 yen. The gold coins were made at the Zōheiryō, the mint in Osaka.
Two Proclamations Issued in Meiji 5
In Meiji 5 (1872), two Dajōkan proclamations concerning the gold coins were issued. The first is Proclamation No. 34 of the 5th day of the 2nd month of Meiji 5. It changed the design on the obverse of the 1 yen gold coin from a coiled dragon to the characters for "one yen." The second is Proclamation No. 341 of the 14th day of the 11th month of Meiji 5. It reduced the diameter of the gold coins and increased their thickness. Under the New Currency Act, the side with the dragon was defined as the obverse (according to the Japan Mint).
Two Types Whose Issue Began in Meiji 5
The Currency Museum document "Coins from the Meiji Era Onward" lists the year in which issue began for each denomination and type of old gold coin. Two of them began in 1872 (Meiji 5): - Old 1 yen gold coin: diameter 13.51 mm, weight 1.66 g. The obverse shows the characters for "one yen." - Smaller type of the old 5 yen gold coin: diameter 21.81 mm, weight 8.33 g. The type whose issue began in 1871 has a diameter of 23.84 mm. According to a note in the same document, rows with the same name differ only in size, thickness and similar points; the design is the same.
List of Denominations and Types
The following list is based on the Currency Museum document "Coins from the Meiji Era Onward." - Old 20 yen gold coin: diameter 35.06 mm, weight 33.3 g. Issue began in 1871 (Meiji 4). - Old 10 yen gold coin: diameter 29.42 mm, weight 16.7 g. Issue began in 1871. The type with a diameter of 29.39 mm began in 1876 (Meiji 9). - Old 5 yen gold coin: diameter 23.84 mm, weight 8.33 g. Issue began in 1871. The type with a diameter of 21.81 mm began in 1872 (Meiji 5). - Old 2 yen gold coin: diameter 17.48 mm, weight 3.33 g. Issue began in 1871. The type with a diameter of 16.96 mm began in 1876. - Old 1 yen gold coin: diameter 13.51 mm, weight 1.66 g. Issue began in 1872 (Meiji 5). The type with a diameter of 12.12 mm began in 1874 (Meiji 7). All are 90% gold and 10% copper. The edges are reeded. The obverse shows a dragon, and the reverse shows the imperial brocade banner and the rising sun. Only the old 1 yen gold coin shows the characters for "one yen" on the obverse.
About the Year "Meiji 5" on a Coin
The year in which issue began and the year struck on a coin are different things. The Japan Mint's record, Zōheikyoku Enkakushi (1921), contains a table of issue amounts by the year shown on the face of the coins. In this table, gold coins with the year "Meiji 3, 4" appear for all five denominations. However, the Mint added a note to this table. Before Meiji 30, there were many cases in which coins made in one year were booked as the next year's, and dies from the previous year were also used in the following year. For this reason, the Mint says the table cannot be taken as fully accurate. For this reason, the public sources checked do not confirm which denominations exist with the year "Meiji 5." Please check the year on the actual coin.
Later Legal Tender Status
In 1897 (Meiji 30), the Coinage Act was enacted and defined 0.75 g of gold as 1 yen. Under the Coinage Act, the gold coins of the New Currency Act were to circulate at twice their face value (according to the Currency Museum catalogue). The old gold coins remained legal tender until March 31, 1988 (Shōwa 63) (according to the Currency Museum document "Coins from the Meiji Era Onward").
How to Check a Coin in Hand
First, measure the weight and the diameter. Compare them with the values in the list above. Even within one denomination, there are types with different diameters. For the old 5 yen and old 1 yen gold coins, tell the types apart by diameter. The old 1 yen gold coin shows the characters for "one yen" on the obverse, not a dragon. To judge whether a coin is genuine, an appraisal by a specialist is the reliable way. How to spot forgeries is covered in An Introduction to Spotting Forgeries. For each denomination, see Old 1 Yen Gold Coin, 5 Yen Gold Coin, 10 Yen Gold Coin and 20 Yen Gold Coin.