WORLD COINS - JAPAN - 10 SEN - CIRCULATION

1940 Japan 10 Sen — Shōwa 15

Aluminum · 22 mm · 1.5 g heavy standard

01 IDENTITY

Coin Identity

CountryJapan

Denomination10 Sen (0.10 Yen)

Calendar Year1940

Japanese EraShōwa 15

Date Inscription昭和十五年 (coin legend arranged right-to-left)

Coin TypeWartime Aluminum 10 Sen

Issue FormatStandard circulation issue

Minting AuthorityJapan Mint

02 PHYSICAL PROFILE

Physical Specifications

CompositionAluminum

Nominal / Variant WeightSee year-specific standard(s) below

1940-dated 1.5 g standard1.5 g · Japan Mint museum specimens: 22.00 mm / 1.50 g

Diameter22 mm type standard; Japan Mint museum specimens measure approximately 21.94–22.04 mm

Catalogue Thickness1.49 mm [Numista N#5438; type-level secondary figure]

ShapeRound

EdgeReeded

Japan Mint museum dimensions are specimen measurements. Numista's 1.49 mm thickness is retained only as a secondary type-level catalogue value and is not treated as an official variant-specific measurement.

03 DESIGN & CONTEXT

Design & Historical Context

Date & Authority Side

A double-petal cherry blossom is flanked by dots, with the national authority above and the Shōwa date below.

Value Side

The reverse uses the chrysanthemum, the 10 Sen denomination and paulownia foliage.

Wartime Context

Japan Mint explains that the 10 Sen and 5 Sen changed to non-holed pure-aluminum coinage in 1940. As aluminum became increasingly important for aircraft, the coin weight was reduced twice during the wartime series.

Artwork & Rights Note

Only independently composed archive text is presented. No third-party Numista photograph, valuation table, logo or copyrighted catalogue illustration is reproduced.

04 ISSUE & MINTAGE

Issue Information

Calendar Year1940

Japanese DateShōwa 15 (昭和十五年)

1940-dated 1.5 g standard — Mintage575,600,000 coins

1940-dated 1.5 g standard — ScopeNumista Y#61.1 places the quantity on the 1940 row and states that the 1941 1.5 g entry is included with year 15; therefore this is not treated as a verified 1940-only annual total.

Japan Mint Annual/Variant Mintage VerificationNot located in the consulted official Japan Mint sources; no secondary grouped figure is promoted to an official annual total

The mintage information above follows the supplied Numista N#5438 year/weight entries and their explicit "included with" notes. Grouped catalogue quantities are preserved with their stated scope instead of being silently assigned to a single calendar year.

05 COLLECTION RECORD

Archive Information

Archive IDJP-10S-1940-SHOWA-AL

Coin Codejp10s40s

QR Short Codejp10s40s

QR Short URLhttps://metacoinart.com/q/jp10s40s

Canonical Path/world-coins/japan/10-sen/1940-1943-showa/1940/

Catalogue Cross-checkNumista N#5438 · Y#61.1 · JNDA#01-30

Archive StatusOfficial type/specimen history documented; grouped mintage retained as secondary catalogue data

06 SOURCES & REFERENCES

References

01 — PRIMARY OFFICIAL COIN-SPECIFIC SOURCE

Japan Mint — Mint Museum Special Exhibition Exhibit Lists

Official Mint Museum records identify the wartime aluminum 10 Sen. The December 2024 list records 1940 specimens at about 22 mm / 1.50 g and 1943 specimens at about 22 mm / 0.98–1.00 g; the August 2024 revised list records a 1941 specimen at 21.98 mm / 1.19 g.

Open 1940/1943 exhibit list · Open 1941 exhibit list

02 — OFFICIAL HISTORICAL SOURCE

Japan Mint — Mint Club No. 78: History of Holed Coins

Japan Mint explains that the 10 Sen and 5 Sen changed to non-holed pure-aluminum coins in 1940 and that, as aluminum became important for aircraft, coin weight was reduced twice.

Open reference

03 — OFFICIAL INSTITUTIONAL CONTEXT

Bank of Japan Currency Museum — Wartime Money

The Currency Museum identifies the 1940 aluminum 10 Sen within the wartime shift from nickel and copper toward aluminum and tin under material shortages.

Open reference

04 — SECONDARY NUMISMATIC CROSS-CHECK

Numista — Japan 10 Sen, Shōwa (N#5438)

Secondary cross-check for year/weight varieties, grouped mintage entries, 22 mm type diameter, 1.49 mm catalogue thickness, reeded edge and Y/JNDA catalogue identifiers. No Numista photographs, valuation table, logo or catalogue prose is reproduced.

Open reference

Independent research archive. ALL THAT CURRENCY is not affiliated with, endorsed by, or sponsored by Japan Mint, Bank of Japan, or Numista. External sources are linked only as identified references.