1 sen coin
The one sen coin was a Japanese coin worth one-hundredth of a Japanese yen, as 100 sen equalled 1 yen. These coins were minted from the late 19th century until the end of World War II. Like the other denominations of sen, these coins were eventually taken out of circulation at the end of 1953.
Composition
| Years | Material |
| 1873–1888 | 98% Copper, 2% Tin and Zinc |
| 1898–1938 | 95% Copper, 4% Tin, 1% Aluminium |
| 1938 | 90% Copper, 10% Zinc |
| 1938–1943 | 100% Aluminium |
| 1944–1945 | 50% Tin, 50% Zinc |
Circulation figures
Meiji
The following are circulation figures for one sen coins that were minted between the 6th, and 42nd year of Meiji's reign. The dates all begin with the Japanese symbol 明治, followed by the year of his reign the coin was minted. Each coin is read clockwise from right to left, so in the example used below "一十二" would read as "year 21" or 1888. Some of the mintages included cover more than one variety of a given coin. Pattern coins from 1869 and 1870 are extremely rare.- "Year" ← "Number representing year of reign" ← "Emperors name"
| Year of reign | Japanese date | Gregorian date | Mintage |
| 6th | 六 | 1873 | |
| 7th | 七 | 1874 | |
| 8th | 八 | 1875 | |
| 9th | 九 | 1876 | |
| 10th | 十 | 1877 | |
| 13th | 三十 | 1880 | |
| 14th | 四十 | 1881 | |
| 15th | 五十 | 1882 | |
| 16th | 六十 | 1883 | |
| 17th | 七十 | 1884 | |
| 18th | 八十 | 1885 | |
| 19th | 九十 | 1886 | |
| 20th | 十二 | 1887 | |
| 21st | 一十二 | 1888 | |
| 25th | 五十二 | 1892 | Unknown |
| 31st | 一十三 | 1898 (Reduced weight | |
| 32nd | 二十三 | 1899 | |
| 33rd | 三十三 | 1900 | |
| 34th | 四十三 | 1901 | |
| 35th | 五十三 | 1902 | |
| 39th | 九十三 | 1906 | Not circulated |
| 42nd | 二十四 | 1909 | Not circulated |
Taishō
The following are circulation figures for one sen coins that were minted between the 2nd and 13th year of Taishō's reign. The dates all begin with the Japanese symbol 大正, followed by the year of his reign the coin was minted. Each coin is read clockwise from right to left, so in the example used below "二十" would read as "year 12" or 1923.- "Year" ← "Number representing year of reign" ← "Emperors name"
| Year of reign | Japanese date | Gregorian date | Mintage |
| 2nd | 二 | 1913 | |
| 3rd | 三 | 1914 | |
| 4th | 四 | 1915 | |
| 5th | 五 | 1916 (Reduced size | |
| 6th | 六 | 1917 | |
| 7th | 七 | 1918 | |
| 8th | 八 | 1919 | |
| 9th | 九 | 1920 | |
| 10th | 十 | 1921 | |
| 11th | 一十 | 1922 | |
| 12th | 二十 | 1923 | |
| 13th | 三十 | 1924 |
Shōwa
The following are circulation figures for one sen coins that were minted between the, and year of Emperor Shōwa's reign. The dates all begin with the Japanese symbol 昭和, followed by the year of his reign the coin was minted. Each coin is read clockwise from right to left, so in the example used below "二十" would read as "year 12" or 1937. The size and weight of one sen coins were dropped significantly in 1938 with the Aluminium "Type 3" issue. Additional modifications of size and weight were also carried out in 1941 and 1944. Coin patterns that include examples struck on porcelain are not included here as they were never issued for circulation. It is unknown how many unofficial locally made clay baked coins circulated.- "Year" ← "Number representing year of reign" ← "Emperors name"
| Year of reign | Japanese date | Gregorian date | Mintage |
| 2nd | 二 | 1927 | 26,500,000 |
| 4th | 四 | 1929 | 3,000,000 |
| 5th | 五 | 1930 | 5,000,000 |
| 6th | 六 | 1931 | 25,001,222 |
| 7th | 七 | 1932 | 35,066,715 |
| 8th | 八 | 1933 | 38,936,907 |
| 9th | 九 | 1934 | 100,004,950 |
| 10th | 十 | 1935 | 200,009,912 |
| 11th | 一十 | 1936 | 109,170,428 |
| 12th | 二十 | 1937 | 133,196,568 |
| 13th | 三十 | 1938 TY1 Cu | 87,649,338 |
| 13th | 三十 | 1938 TY2 Br | 113,600,000 |
| 13th | 三十 | 1938 TY3 Al | 45,502,266 |
| 14th | 四十 | 1939 | 444,602,146 |
| 15th | 五十 | 1940 | 601,110,015 |
| 16th | 六十 | 1941 | 1,016,620,734 |
| 17th | 七十 | 1942 | 119,709,832 |
| 18th | 八十 | 1943 | 1,163,949,434 |
| 18th | 八十 | 1943 | 627,160,000 |
| 19th | 九十 | 1944 | 1,629,580,000 |
| 20th | 十二 | 1945 | Unknown |