the nuclear accident at Tokai, Ibaraki. Physicists Masuchika Kohno and Yoshinobu Koizumi showed how the coin could be used to estimate neutron dosage to the surrounding population, by measuring its zinc isotope ratios. They concluded that the coin could offer information about the total neutron effect during the accident. The coins could also give insight about shielding modern Japanese houses as the coins were recovered from indoors. Very few five yen coins were minted between 2009 and 2013 making them premium coins for collectors as coins for the latter four years are confined to mint sets. This was due to an increase in the usage of electronic currency which inhibited demand for new coins. Mintage figures recovered in 2014 as general production resumed until 2022, when 5 yen coins were again confined to mint sets. 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. Several different interpretations of this "luck" exist depending on how many five yen coins are offered. While it is generally said that offering "lucky" 5 yen coins as tribute is good, there are others who disagree. Those who hold this position state that "perforated coins" such as "5 yen" and "50 yen" are unlucky due to their central holes. Shrines in general depend on offerings in either case to fund maintenance, repairs, and operations for the deity or deities enshrined. There are also other forms of offerings welcomed at shrines depending on the place and customs allowed. According to a priest at Chichibu Shrine, harvested rice was historically given as Shinto deities do not like cash itself as tribute. Five yen coins are also sometimes given as gifts of "good fortune" during the Japanese New Year. These gifts are traditionally given to children in decorated envelopes called , with the total amount of money included depending on age. Composition Circulation figures Meiji The following are circulation figures for the coins that were minted between the 3rd, and the 45th and last year of Meiji's reign. Coins for this period all begin with the Japanese symbol 明治 (Meiji). One yen trade dollars and/or patterns are not included here.