Issued, prepared, and unverified

Emergency Coin Materials

Compare issued aluminum, tin, and tin-zinc types with unissued ceramic preparation and the unverified domestic-iron claim.

非常用貨幣材料

Obverse of the Showa 16 (1941) 1 Sen of Japan — As6673, CC BY-SA 3.0, via Wikimedia Commons; deterministic crop and conversion. · Representative contextual pair

Reverse of the Showa 16 (1941) 1 Sen of Japan — As6673, CC BY-SA 3.0, via Wikimedia Commons; deterministic crop and conversion. · Representative contextual pair

Core routes: 20
Issue studies: 14
Exact image pairs: 15
Indexable routes: 0

Context

Historical and monetary setting

Material labels must express legal status as well as chemistry. An emergency object can be officially manufactured yet never issued.

Identification

How to classify the object

For aluminum check mass and oxidation; for tin check softness and granular surfaces; for tin-zinc use the official alloy and dimensions. Do not perform destructive testing.

Evidence boundary

What this page does not claim

Porcelain, ceramic, fiber, glass, and iron labels require object-level official evidence. Dealer wording is not sufficient.

issued circulation

aluminum

Very light; vulnerable to oxidation, scratches, bends, staining, and edge damage.

The official table records repeated wartime weight reductions and a 1946 bridge issue.

issued circulation

tin

Soft alloy with darkening, spotting, bends, and granular surface risks.

Official specifications identify 93% tin and 7% zinc.

verified emergency circulation

tin-zinc

A late-war 50:50 alloy requiring careful surface and mass comparison.

The official issue table lists the composition, size, and mass.

production preparation; unissued

ceramic

Brittle nonmetallic preparations; survivals do not prove circulation.

Japan Mint states ceramic 1 Sen pieces were manufactured in 1945 but not issued.

unverified for issued domestic national coinage

iron

Rust, pitting, plating loss, and stabilization would be central if an official object were established.

No issued domestic iron type appears in the controlling Bank of Japan and Japan Mint national issue tables reviewed for this phase.

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Related Taisho–Showa references

Shōwa Coinage: Prewar, Wartime, and Transition Taishō and Shōwa Coinage Taishō Coinage Early Shōwa Prewar Coinage Wartime Japanese Coinage Postwar Coinage Transition

Evidence

Sources and scope

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

150 Years of the Japan Mint Japan Mint

Institutional history, Temporary Currency Act, strategic-metal substitutions, ceramic production, surrender, occupation supervision, and postwar scrap reuse.

Open source

Coin FAQ Japan Mint

Obverse/reverse convention, unissued ceramic status, postwar brass scrap composition, edge changes, and later silver-to-cupronickel transition.

Open source

Special exhibition object list: Japan Mint and war Japan Mint Museum

Object-level measured examples of nickel, aluminum-bronze, aluminum, tin, and tin-zinc wartime coins.

Open source