Tenpo-Oban (Large-Sized Gold Coin of the Tenpo Era) (天保大判)
Tenpo-Oban refers to a large-sized gold coin issued from August 13, 1838. It was not issued because of currency reform, and it was similar in shape to and close in gold quality to Kyoho-Oban (large-sized coin of the Kyoho era), and was also called fukimashi Oban or fukitsugi Oban.
Go-ryo ban (five-ryo coin) minted from August 1837 was originally the idea of Shinjo GOTO the fifteenth of Obanza (an organization associated with minting); however, the coin is also said to have been intended for bail-out measure for the organization because Oban minting emerged at the time when the organization was struggling to cope with economic difficulties after they had lost the role to mint coins to kin-za (an organization in charge of casting and appraising of gold during the Edo period) because the coin was currency.
Summary
It had the letters '拾両後藤 (written seal mark)' (ten-ryo Goto) written with indian-ink by Hojo GOTO the sixteenth and Tenjo the seventeenth on its surface, and it was a little angular, oval coin with a hallmark of paulownia in a circle each on the upper, lower, left and right parts of it. It was distinguishable from Kyoho-Oban for reasons including the thickness of the engraved short lines and the different figures of hallmarks on its surface.
In addition to hallmarks of paulownia patterns in a circle and in a hexagon and written seal mark at the center on its back, a hallmark of hereditary officer was engraved on the lower left.
When it comes to minting output by hallmark on the back, between August 10 and October 16, 1838, two (sample gold) coins with '方, 次, 丘' (kata, tsugi, oka), 243 coins with '伊, 三, 丘' (i, three, oka), 224 coins with '伊, 文, 丘' (i, bun, oka), 154 coins with '伊, 次, 丘' (i, tsugi, oka) were minted and seven out of the above-mentioned were crushed; between November 12, 1838, and January 16, 1839, 156 coins (hallmarks unconfirmed) were minted; and between January 15, 1841, and June 10, 1841, in total, 1,115 coins with either 'い, 宇, 川' (i, u, kawa), or 'は, 宇, 川' (ha, u, kawa) were minted.
While the price of the Oban was supposed to be eleven-ryo three-bu to Genbun-Koban according to the content of gold, the actual price was fixed at ten-ryo. Under such a circumstance, merchants stored the Oban away, which led to a lack of Oban available, and later the Oban prices which had climbed to twenty-ryo to Bunsei-Koban and thirty two-ryo to Tenpo-Koban were lowered and settled at twenty-ryo two-bu because of the issuance of Tenpo-Oban.
The currency was used from August 13, 1838 to May 30, 1860, concurrently with Kyoho-Oban.