Friday, November 23, 2012

Reading Japanese Numbers and Dates

Japan 1945 10-sen
As I've previously discussed, it is useful for a world coin collector to be able to read numbers and dates in different languages. This allows you to determine the proper date and denomination of a coin. That information, along with the coin's country, is the minimum you'd need to look up the coin in a guide, check if it's in your collection, or trade with another collector.

The Chinese Numerals

Japanese is one such language which doesn't use Arabic numerals (0, 1, 2...). Japanese uses a number-writing system that is shared with the Chinese language, and is generally referred to as the Chinese numerals.  The symbols used to represent 0 through 10 are pictured below, with their European/Arabic equivalent:
Japanese numbers 0 through 10
Numbers above (and including) 10 are not made by combining individual digits, like in the Arabic numeral system. Instead, Japanese uses combinations of numerals which add and/or multiply to the number being written. For example, 11 is not written 一一 (1 1) - it is 十一 (10 1, or 10 + 1). 15 is written as 十五 (10 + 5). 20 is 二十 (2 10, or 2 * 10), and 22 is 二十二 (2 10 2, or 2 * 10 + 2).

There are additional Japanese symbols for larger multiples of 10:
   100: 百
   1000: 千

The Japanese number-writing system is known as a non-positional numeral system because individual symbols don't identify their value strictly based on their position in the number. For example, 40 (四十, 4 10), 400 (四百, 4 100), and 4000 (四千, 4 1000) all use exactly 2 symbols in Japanese (while the Arabic numbers 40, 400, and 4000 use 2, 3, and 4 respectively). The position of a symbol doesn't define its value; its effect on or by its neighbors does.

More examples of Japanese numbers:
   32: 三十二
   44: 四十四
   78: 七十八
   99: 九十九

Japanese Dates

In the late 1800s, Japan adopted the Gregorian calendar, but with a starting date (a "year zero") that corresponded to the Gregorian calendar's year 660 BC, making Japan's year values larger than the year used by other countries (i.e. 1920 A.D. = 2580 Japan). This practice largely stopped after World War 2, and for most purposes Japan uses the same year as America would use.

Modern Japanese coins, however, use the Japanese era calendar to indicate when a coin was minted. An era starts counting years at 1 with each new Japanese emperor. The date is indicated by the emperor's era name (using its Kanji symbols) followed by the year of the emperor's reign. For example, 1989 was the first year for the current Heisei era (under Emperor Kinjo, or Akihito), so coins minted that year would contain the symbol for the Heisei era (平成)  and the symbol for 1 (一).

Japan's era name examples
Fortunately for those who don't read Japanese, there have only been 4 Japanese eras since 1900:
  • 明治 (Meiji) 1867 - 1912
  • 大正 (Taisho) 1912 - 1926
  • 昭和 (Showa) 1926 - 1989
  • 平成 (Heisei) 1989 - present

On Japanese coins, the date is usually read clockwise (right-to-left). It begins with the symbols for the era name (see the list above), followed by the era year, and ends with the symbol for year (年). While most coins are read right-to-left, some need to be read left-to-right (counter-clockwise). The symbol for year (年) is always at the end of the date, so if you see it at the left-hand end of a number, read it from right-to-left; if you see it at the right-hand end, read it left-to-right.

Examples from actual Japanese coins:
Left to right: 1921 10-sen, 1942 10-sen, 1995 5-yen, 1974 10-yen
From left to right:
  • Taisho year 10 - read clockwise
  • Showa year 17 (10 + 7) - read clockwise
  • Heisei year 7 - read counter-clockwise
  • Showa year 49 (4 * 10 + 9) - read left-to-right 

Showa year 48 100-yen Japanese coin
On recent 50- and 100-yen coins (since 1967), the era year is shown in Arabic numerals instead of Japanese numerals, like the coin pictured here. The rest of the date is read the same way described above - counter-clockwise, starting with the era name and ending with the year symbol (年).

Calculating the Gregorian Date

Once you know the era name and year, you can calculate the Gregorian year using the era table above. Take the era's starting year, add the era year, and subtract 1. For example, Heisei year 3 would correspond to 1991 (year 1 is 1989, year 2 is 1990, and year 3 is 1991). Here are the dates for the coins pictured above:
  • Taisho year 10 = 1912 + 10 -1 = 1921
  • Showa year 17 = 1926 + 17 - 1 = 1942
  • Heisei year 7 = 1989 + 7 - 1 = 1995
  • Showa year 49 = 1926 + 49 - 1 = 1974
  • Showa year 48 = 1926 + 48 - 1 = 1973
Taiwan 1972 1-yuan (year 61)

Comparison to Taiwan Coins

Coins from Taiwan use the same number symbols as Japanese coins, so it is easy to mistake them for each other. In the coin pictured here, the year reads 6 10 1 (61, in yellow highlighting) reading counter-clockwise and ending with the year symbol (年). Taiwan coins will of course not have one of the 4 Japanese emperor era names listed above, and frequently have the flower symbol shown here.