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958

Kengen Taihō: Imperial Coin No. 12

Issued in 958, Kengen Taiho was the final new issue in the official ancient court sequence. Domestic coin issuance then ceased for centuries while commodity money and, later, imported Chinese cash filled monetary roles.

乾元大寶Kengen Taihō

Representative Kengen Taihō from the Tokyo National Museum Kōchō Jūnisen group Other face not present in the approved source
Representative source face; the other face is unavailable.National Institutes for Cultural Heritage, Japan / ColBase · CC BY 4.0
Sequence
12 / 12
Issue year
958
Era
天徳 2
Authority
Imperial court under Emperor Murakami

Historical context

Issued in 958, Kengen Taiho was the final new issue in the official ancient court sequence. Domestic coin issuance then ceased for centuries while commodity money and, later, imported Chinese cash filled monetary roles.

Inscription and reading

乾元大寶 · Kengen Taihō · Kengen Taiho

Reading confidence · high

Observed catalog specimens

Measurements, metal, and cast fabric

These values are comparative observations, not official tolerances or authentication cutoffs.

Weight
2.83 g (1 observed specimen)
Diameter
19.96 mm (1 observed specimen)
Metal
copper alloy
Hole
central square hole
Rims
small late-series cast fabric, often weak
Casting
cast copper-alloy cash coin

Composition evidence

Sampled late issues are low-tin and often lead-rich copper alloys; the catalog does not support one universal formula.

Low-tin, often lead-rich Cu alloy tendency in sampled late coins.

Attribution boundary

A named court and era establish issue context. They do not establish the physical mint of an unidentified specimen.

high for identity, issue date, authority, and final-sequence position; low for generalized measurements because only one catalog specimen was measurable

Condition and authenticity

weak or incomplete legends, corrosion, and cast porosity require separate recording

Open cast-coin 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 Currency Museum, Bank of Japan

Fuhonsen and Mumon Ginsen context, the 708 issue of Wado Kaichin, state monetary policy, quality decline, the 958 final issue, and the return to commodity money.

Open source
Wado Kaichin and Ancient Coinage Exhibition Catalogue, Pages 11–15 Currency Museum, Bank of Japan

Issue dates, emperors, policy evidence, production decline, and historical notes for Ryuhei Eiho through Kengen Taiho.

Open source
Measurement Catalog for Ancient Coin Types from Mannen Tsuho through Kengen Taiho Currency Museum, Bank of Japan

Specimen-level outer diameter and weight observations for issues two through twelve; observations are not statutory standards.

Open source
Chemical Composition Study of the Twelve Ancient Coin Types Institute for Monetary and Economic Studies, Bank of Japan

Measured copper, tin, lead, iron, arsenic, and antimony patterns across sampled ancient coins, with specimen-level limitations.

Open source