Late Tokugawa emergency reform

Ansei and Man’en Recoinages

Compare the Koban, Nibukin, and silver measures used before and during the Man’en response to foreign-trade pressure.

安政・万延の改鋳

Obverse of a representative Man’en Koban, retaining its oval form — As6673 · CC BY-SA 3.0 · exact type representative

Reverse of a representative Man’en Koban, retaining its oval form — As6673 · CC BY-SA 3.0 · exact type representative

Core routes: 15
Issue studies: 12
Cleared image pairs: 10
Indexable routes: 27

Context

Historical and monetary setting

The reform sequence included short-lived experiments, changes to declared-value gold, and a reduced Man’en Koban. Earlier Tokugawa pieces continued to complicate the circulating mix.

Identification

How to classify the evidence

Compare name, date, form, mass, catalog fineness, predecessor, successor, and reform purpose. Catalog values are not authentication cutoffs.

Evidence boundary

What this page does not claim

Late Tokugawa reforms remain Tokugawa issues unless a transition record explicitly documents a Meiji continuation.

Comparison

Late Tokugawa emergency standards

Image	Issue	Years	Value	Form	Mass	Fineness	Reform purpose
Not available	Ansei Koban	1859	1 ryō	oval	8.97 g	57%	Late Tokugawa adjustment immediately before the Man’en emergency standard.
Representative contextual image: Obverse and reverse of a representative Man’en Koban, retaining its oval form.↗	Man’en Koban	1860–1867	1 ryō	oval	3.3 g	57%	Reduced pure-gold content to bring Japan’s monetary relationship closer to international conditions and curb outflow.
Not available	Ansei Nibukin	1856–1860	2 bu	rectangular	—	57%	Fractional gold for the late Tokugawa declared-value system.
Not available	Man’en Nibukin	1860–1869	2 bu	rectangular	—	22%	Large emergency issue after the Man’en reform; its low gold content and scale contributed to inflation.
Not available	Ansei Nishu-gin	1859	2 shu	rectangular	—	85%	Issued just before port opening in an unsuccessful attempt to align two coins with one foreign silver dollar.

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Related transition references

Bakumatsu and Early Meiji Coinage Foreign Silver in Japan New Currency Act of 1871 Early Meiji Gold Coinage Early Meiji Silver Coinage Early Meiji Copper and Bronze Coinage Japanese era-date guide

Evidence

Sources and scope

These links support the claims on this page. Source authority does not imply permission to republish source images.

History of Japanese Currency: Opening of the Country and Gold Outflow Bank of Japan Currency Museum

Treaty-port exchange, Mexican dollars, gold outflow, Man’en reform, transitional currency, and the 1871 decimal system.

Open source

Late Tokugawa coin display records Bank of Japan Currency Museum

Museum catalog fineness values for Ansei and Man’en gold and silver issues.