5 yen coin
Encyclopedia
The is one denomination of Japan
ese yen. The current design was first minted in 1959 using Japanese characters known as the "new script
", and were also minted from 1949-1958 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 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, forestry 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 Western numerals on either face.
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
shrine
s 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.
at Tokai, Ibaraki
in 1999, physicist
s 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:
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.
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
ese yen. The current design was first minted in 1959 using Japanese characters known as the "new script
Shinjitai
Shinjitai are the forms of kanji used in Japan since the promulgation of the Tōyō Kanji List in 1946. Some of the new forms found in shinjitai are also found in simplified Chinese, but shinjitai is generally not as extensive in the scope of its modification...
", and were also minted from 1949-1958 using "old-script" Japanese characters
Shinjitai
Shinjitai are the forms of kanji used in Japan since the promulgation of the Tōyō Kanji List in 1946. Some of the new forms found in shinjitai are also found in simplified Chinese, but shinjitai is generally not as extensive in the scope of its modification...
. Five-yen coins date to 1870 (when, due to the much higher value of the yen, they were minted in gold
Gold
Gold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...
).
The front of the coin depicts a rice
Rice
Rice is the seed of the monocot plants Oryza sativa or Oryza glaberrima . As a cereal grain, it is the most important staple food for a large part of the world's human population, especially in East Asia, Southeast Asia, South Asia, the Middle East, and the West Indies...
plant growing out of the water, with "five yen" written in kanji
Kanji
Kanji are the adopted logographic Chinese characters hanzi that are used in the modern Japanese writing system along with hiragana , katakana , Indo Arabic numerals, and the occasional use of the Latin alphabet...
; 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, forestry and fisheries, the key elements of the Japanese first-sector economy. Around a hole, there is a gear
Gear
A gear is a rotating machine part having cut teeth, or cogs, which mesh with another toothed part in order to transmit torque. Two or more gears working in tandem are called a transmission and can produce a mechanical advantage through a gear ratio and thus may be considered a simple machine....
that represents industry. It is the only Japanese coin in circulation to lack Western numerals on either face.
Cultural significance
The Japanese for "five yen," go en (五円) is a homophoneHomophone
A homophone is a word that is pronounced the same as another word but differs in meaning. The words may be spelled the same, such as rose and rose , or differently, such as carat, caret, and carrot, or to, two, and too. Homophones that are spelled the same are also both homographs and homonyms...
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
Shinto
or Shintoism, also kami-no-michi, is the indigenous spirituality of Japan and the Japanese people. It is a set of practices, to be carried out diligently, to establish a connection between present day Japan and its ancient past. Shinto practices were first recorded and codified in the written...
shrine
Shrine
A shrine is a holy or sacred place, which is dedicated to a specific deity, ancestor, hero, martyr, saint, daemon or similar figure of awe and respect, at which they are venerated or worshipped. Shrines often contain idols, relics, or other such objects associated with the figure being venerated....
s 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
Wallet
A wallet, or billfold, is a small, flat case that is used to carry personal items such as cash, credit cards, identification documents , photographs, business cards and other paper or laminated cards...
before inserting any other money.
Use in nuclear accident investigation
Following the nuclear accidentTokaimura nuclear accident
The Tokaimura nuclear accident , which occurred on 30 September 1999, resulted in two deaths. At that time, it was Japan's worst civilian nuclear radiation accident. The criticality accident occurred in a uranium reprocessing facility operated by JCO , a subsidiary of Sumitomo Metal Mining Co...
at Tokai, Ibaraki
Tokai, Ibaraki
is a village located in Naka District, Ibaraki, Japan. It is approximately 120 km north of Tokyo, Japan on the Pacific coast.As of 1 January 2005, the village has an estimated population of 35,467 and a population density of 946.29 persons per km²...
in 1999, physicist
Physicist
A physicist is a scientist who studies or practices physics. Physicists study a wide range of physical phenomena in many branches of physics spanning all length scales: from sub-atomic particles of which all ordinary matter is made to the behavior of the material Universe as a whole...
s Masuchika Kohno and Yoshinobu Koizumi showed how this coin could be used to estimate neutron
Neutron
The neutron is a subatomic hadron particle which has the symbol or , no net electric charge and a mass slightly larger than that of a proton. With the exception of hydrogen, nuclei of atoms consist of protons and neutrons, which are therefore collectively referred to as nucleons. The number of...
dosage to the surrounding population, by measuring its zinc
Zinc
Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
isotope
Isotope
Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation...
ratios. They write:
- The Japanese 5-yen coinCoinA coin is a piece of hard material that is standardized in weight, is produced in large quantities in order to facilitate trade, and primarily can be used as a legal tender token for commerce in the designated country, region, or territory....
is about 22 millimeters in diameterDiameterIn geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints are on the circle. The diameters are the longest chords of the circle...
and 1.5 mm thick, weighs 3.75 gramGramThe gram is a metric system unit of mass....
s and has a central hole 5 mm wide. We chose this coin for monitoring neutron exposure because it is widely circulated, the zincZincZinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
content is precisely controlled, and the
generated has a convenient half-lifeHalf-lifeHalf-life, abbreviated t½, is the period of time it takes for the amount of a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but it may apply to any quantity which follows a set-rate decay.The original term, dating to...
(244.1 days) and gamma rayGamma rayGamma radiation, also known as gamma rays or hyphenated as gamma-rays and denoted as γ, is electromagnetic radiation of high frequency . Gamma rays are usually naturally produced on Earth by decay of high energy states in atomic nuclei...
energy emission (1,115.5 keVKevKev can refer to:*Kev Hawkins, a fictional character.*Kevin, a given name occasionally shortened to "Kev".*Kiloelectronvolt, a unit of energy who symbol is "KeV".* Krefelder Eislauf-VereinKEV can refer to:...
). 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.
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.
