5 yen coin

Five yen

Japan
Value	5 Japanese yen
Mass	3.75 g
Diameter	22 mm
Thickness	1.5 mm
Center hole diameter	5 mm
Composition	c. 65% Cu c. 35% Zn
Years of minting	1948–1958 (Old style) 1959–present (New style)
Catalog number	KM 72, 72a, 96.1 and 96.2
Obverse
Design	Rice ,water and gear
Designer	"Old script"
Reverse
Design	Tree sprouts
Designer	"new script"

The 5 yen coin (五円硬貨 Go-en kōka) is one denomination of Japanese yen. The current design was first minted in 1959 using Japanese characters known as the "new script", and were also minted from 1948-1958 using "old-script" Japanese characters. Five-yen coins date to 1870 (when, due to the much higher value of the yen, they were minted in gold). The modern-day coin was first produced in 1948 with a different styled inscription. This was changed in 1959 and the design has remained unchanged since.

The front of the coin depicts a rice plant growing out of the water, with "five yen" written in kanji; the back is stamped with "Japan" and the year of issue, also in kanji, separated by sprouts of a tree. The three graphic elements of the coin represent agriculture and fisheries, the key elements of the Japanese first-sector economy. Around a hole, there is a gear that represents industry. It is the only Japanese coin in circulation to lack Arabic numerals on either face.

Cultural significance

The Japanese for "five yen," go en (五円) is a homophone with go-en (御縁), "en" being a word for causal connection or relationship, and "go" being a respectful prefix. As a result, five-yen coins are commonly given as donations at Shinto shrines with the intention of establishing a good connection with the deity of the shrine, and is widely believed it is best to insert a single five-yen coin into a new wallet before inserting any other money.

Use in nuclear accident investigation

Following the nuclear accident at Tokai, Ibaraki in 1999, physicists Masuchika Kohno and Yoshinobu Koizumi showed how this coin could be used to estimate neutron dosage to the surrounding population, by measuring its zinc isotope ratios. They write:

The Japanese 5-yen coin is about 22 millimeters in diameter and 1.5 mm thick, weighs 3.75 grams and has a central hole 5 mm wide. We chose this coin for monitoring neutron exposure because it is widely circulated, the zinc content is precisely controlled, and the ${}^{{65}}{{\rm {Zn}}}$ generated has a convenient half-life (244.1 days) and gamma ray energy emission (1,115.5 keV). To obtain a record of the dosage of neutrons released as a result of the accident, we collected exposed coins from people's houses at distances 100–550 m from the facility.^[1]

They concluded that the coin could offer information about the total neutron effect during the accident, and about shielding by modern Japanese houses, given that the coins were recovered from indoors.

Circulation figures

Showa

The following are circulation dates which cover Emperor Hirohito's reign. The dates below correspond with the 23rd to the 64th year (last) of his reign. All five yen coins that were made before 1959 use Shinjitai, or old script Japanese. In 1949 only, two different styles of writing were used before a more modern one was established in 1950. This second style of writing was used until 1958 when the current script of Japanese took its place in the following year. Coins for this period will all begin with the Japanese symbol 昭和 (Showa).

• Japanese coins are read with a left to right format:

"Emperors name" -> "Number representing year of reign" -> "Year" (Ex: 昭和 -> 三十四 -> 年).

* = First style
** = Second style
^ = Third style

Year of reign	Japanese date	Gregorian date	Mintage[2]
23rd	二十三	1948 *	74,520
24th	二十四	1949 *	179,692
24th	二十四	1949 **	111,896
25th	二十五	1950	181,824
26th	二十六	1951	197,980
27th	二十七	1952	55,000
28th	二十八	1953	45,000
29th	二十九	1954	0
30th	三十	1955	0
31st	三十一	1956	0
32nd	三十二	1957	10,000
33rd	三十三	1958 **	50,000
34th	三十四	1959 ^	33,000
35th	三十五	1960	34,800
36th	三十六	1961	61,000
37th	三十七	1962	126,700
38th	三十八	1963	171,800
39th	三十九	1964	379,700
40th	四十	1965	384,200
41st	四十一	1966	163,100
42nd	四十二	1967	26,000
43rd	四十三	1968	114,000
44th	四十四	1969	240,000
45th	四十五	1970	340,000
46th	四十六	1971	362,050
47th	四十七	1972	562,950
48th	四十八	1973	745,000
49th	四十九	1974	950,000
50th	五十	1975	970,000
51st	五十一	1976	200,000
52nd	五十二	1977	340,000
53rd	五十三	1978	318,000
54th	五十四	1979	317,000
55th	五十五	1980	385,000
56th	五十六	1981	95,000
57th	五十七	1982	455,000
58th	五十八	1983	410,000
59th	五十九	1984	202,850
60th	六十	1985	153,150
61st	六十一	1986	113,960
62nd	六十二	1987	631,775
63rd	六十三	1988	396,120
64th	六十四	1989	67,332

Heisei

The following are circulation dates in the reign of the current Emperor. Akihito was crowned in 1989, which is marked with a 元 symbol on the coin as a one year type. Coins for this period all begin with the Japanese symbol 平成 (Heisei).

• Japanese coins are read with a left to right format:

"Emperors name" -> "Number representing year of reign" -> "Year" (Ex: 平成 -> 三 -> 年).

Year of reign	Japanese date	Gregorian date	Mintage[2]
1st	元	1989	960,660
2nd	二	1990	520,953
3rd	三	1991	517,120
4th	四	1992	301,130
5th	五	1993	413,240
6th	六	1994	197,767
7th	七	1995	351,874
8th	八	1996	207,213
9th	九	1997	239,086
10th	十	1998	172,612
11th	十一	1999	60,120
12th	十二	2000	9,030
13th	十三	2001	78,025
14th	十四	2002	143,662
15th	十五	2003	102,406
16th	十六	2004	70,903
17th	十七	2005	16,029
18th	十八	2006	9,594
19th	十九	2007	9,904
20th	二十	2008	9,811
21st	二十一	2009	4,003
22nd	二十二	2010	510
23rd	二十三	2011	456
24h	二十四	2012	659
25th	二十五	2013	554
26th	二十六	2014	87,538
27th	二十七	2015	105,004
28th	二十八	2016	-

References

1. Kohno, Masuchika; and Yoshinobu Koizumi (2000). "Tokaimura accident: Neutron dose estimates from 5-yen coins". Nature. 406 (6797): 693. doi:10.1038/35021138. PMID 10963586.
2. "Circulation figures" (PDF). Japan Mint. Retrieved August 27, 2016.

External links

• The front sides of two five yen coins.