Just about all modern Japanese coins are really cool. Their designs are artistic and very interesting. Flowers are a recurring theme. These are cherry blossoms.
The date of these coins is keyed to the start of the reigning dynasty. Arabic numerals on the '100' side give the years elapsed since the beginning of the dynasty, either Showa (emperor Hirohito) or Akihito (emperor Heisei). You can figure the Gregorian date on these coins by adding a start date to the numeral shown. For numerals greater than 41, add 1925 (start of the Showa dynasty). For numerals less than 41, add 1988 (start of the Akihito dynasty). For instance, if the numerals are 55, the Gregorian year is 1925 + 55 = 1980AD; if the numerals are 12, the Gregorian year is 1988 + 12 = 2000AD.
These coins are made of copper nickel and are worth face value (100 yen in Japan). Use a web site such as xe.com to convert currency values.
Should you have a specimen that is absolutely, fully uncirculated, a collector would probably pay a few US dollars over face value to add it to his or her collection.
The years 42, 44, 13, and 14 are slightly less common when fully uncirculated. Such a coin catalogs for about $8.
be sure to refer to our 'Important Terminology' page on the top left to interpret what 'catalog value' really means.