Representative Edo issue

Keicho Koban: Foundational Tokugawa One-Ryo Gold

The Keicho Koban anchors the early Tokugawa declared-value gold branch and the long Koban recoinage sequence.

慶長小判Keichō Koban

Keicho Koban obverse — As6673 · CC BY-SA 3.0 · Representative image; not the exact image of every issue described on this page.

Keicho Koban reverse — As6673 · CC BY-SA 3.0 · Representative image; not the exact image of every issue described on this page.

Years: From 1601
Metal branch: gold
Value or unit: 1 ryo
Catalog fineness: 84%

Context

Historical and monetary setting

Issued from 1601 as Tokugawa control over gold and silver production was consolidated.

Identification

How to classify the object

Attribute only by matching punches, calligraphy, fabric, mass, fineness context, and specialist diagnostics; an oval gold shape alone is insufficient.

Evidence boundary

What this page does not claim

Museum display tables and analytical research use different fineness frames; both remain source-labelled.

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Related Edo references

Genbun Koban: The 1736 Gold Recoinage Manen Koban: The Small Final Tokugawa Koban Standard

Evidence

Sources and scope

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

Early Edo Gold Recoinages Bank of Japan Currency Museum

Keicho through Kyoho Koban display-table masses and fineness values.

Open source

Non-destructive Analysis of the Fineness of Kobans in the Yedo Period Institute for Monetary and Economic Studies, Bank of Japan

Analytical measurements, specimen variation, and qualification of nominal fineness.

Open source