The early coins with a square hole are called cash. They were made by sand casting and are usually a type of copper alloy, though some were made of iron. In Japan there are a few basic types of cash coins that were cast over a long period of time. There are different varieties which I will list if important to dating or other things. The basic cash coin is a mon. There are 4 mon coins as well. There are also coins made for trade with other countries during the 1600s, which are collectively called Nagasaki trade coins. They copy the legends of earlier Chinese coins, and use a variety of scripts. After the end of the shogunate in the 1870s, Japan started minting coins using modern minting equipment. The new coins were based on the yen of one hundred sen and one thousand rin. They included the era name of the current emperor and the year of that era name, along with the country name. On some of them, I can’t see the date, so you can learn the numerals and attribute them yourself. If you want to,before 1948 the numerals read right to left, and left to right afterwards. Also, with respect to cash coins I am not an expert, but David Hartill’s book on Japanese coins helps with specifics on dating. Era names Meiji 1-45 (1868-1912) Taisho 1-15 (1912-1926) Showa 1-64 (1926-1988) By the numbers on the binder 1- 4 mon Kan’ei Tsuho (1769-1860) 2- 4 mon (most likely Kan’ei Tsuho) 3- 4 mon Bunkyu Eiho (1863-1867) Bun written differently, standard Ho 4- Kan’ei Tsuho (Bun mintmark)* (1668-1700) 5- Tenpo Tsuho (100 mon) (1838-1870) 6- as 4 7- as 4, possibly different mint 8- as 4, iron, possible mintmark, possibly no mintmark) 9- as 4, (1716-1860) 10- as 4, no mintmark, Ho old style, so (1636-1668) 11- as 4 (Gen mintmark (Osaka mint)) 12- Nagasaki trade coin Genpo Tsuho (seal script) 13- ditto, Kinei Tsuho (regular script) 14- 50 sen Showa 21-22 (1946-47) 15- 5 sen Showa 13-15 (1938-40) 16- 2 sen Meiji 15 17- 1 sen Meiji 6-21 18- 1 sen Taisho 5-13 (1916-1924) or Showa 2-13 (1927-38) 19- ditto 20- 10 sen Showa 13-15 (1938-40) 21- 10 sen Showa 20-21 (1945-46) 22- 10 sen Showa 15-18 (1940-43)** 23- 5 sen Showa 15-18 (1940-43)** 24- as 22, Showa 16 (1941)** 25- as 23, Showa 18 (1943)** 26- 10 sen Showa 19 (1944) 27- 5 sen Showa 20-21 (1945-46) 28- 10 sen Taisho 9-15 1920-26) or Showa 2-7 (1927-32) 29- 5 sen Taisho 9-12 (1920-23) or Showa 7 (1932) 30- 1 yen Showa 23-25 (1948-50) 31- 50 sen Showa 22 (1947) 32- 1/2 sen Meiji 6-21 33- 1 sen Showa 13-15 (1938-40) 34- 1 sen Showa 16-18 (1941-43)** 35- 1 sen Showa 19-20 (1944-45) *the bun mintmark signifies it was minted in the city of Edo (now called Tokyo) ** during the Second World War there was a weight reduction of the coins once the Japanese got desperate. The weight is as follows: 1 sen Years 16-18: 0.65 grams Yr 18: 0.55 g 5 sen Yrs 15-16: 1.2 g Yrs 16-17: 1.0 g Yr 18: 0.8 g 10 sen Yrs 15-16: 1.5 g Yrs 16-17: 1.2 g Yr 18: 1 g
