1927–1938 Japan 1 Sen — Shōwa Paulownia Bronze Type
Shōwa 2–13 · bronze · official standard Cu 95% / Sn 4% / Zn 1% · 23.03 mm · 3.75 g
Select a Year
A page is retained for every calendar year from 1927 through 1938. The supplied Numista table contains no 1928 row, so 1928 is preserved as a non-listed year page without inventing a zero mintage.
Paulownia Bronze 1 Sen
Japan Mint history records the 1916 reduction of the 1 Sen bronze coin and the 1938 wartime transition away from bronze. Bank of Japan Currency Museum specifications for the reduced bronze standard are Cu 95%, Sn 4%, Zn 1%, 23.03 mm and 3.75 g. The supplied Numista N#13954 table identifies the Shōwa dated run from 1927 through 1938, with no 1928 entry.
Official Sources & Catalogue Cross-check
Japan Mint — 150 Years of History
Japan Mint records the 1916 reform that reduced the diameter and weight of the 1 Sen bronze coin and later explains that, under the Temporary Currency Act in 1938, the 1 Sen bronze coin was changed to brass as wartime material policy altered coinage.
Japan Mint — Mint Museum Guide
The Japan Mint Museum guide documents the 1938 Temporary Currency Act and the replacement wartime 1 Sen brass and aluminum issues, providing the official context for the end of the earlier bronze 1 Sen phase.
Bank of Japan Currency Museum — Coins Since the Meiji Era
The Bank of Japan Currency Museum lists the reduced-size 1 Sen bronze standard introduced in 1916 as copper 95%, tin 4%, zinc 1%, plain edge, 23.03 mm diameter and 3.75 g weight. This official specification is used as the physical standard for the continuing Shōwa bronze type.
Numista — Japan 1 Sen, Shōwa (N#13954)
Secondary cross-check for Shōwa 2–13 dated issues, annual mintage figures, the 23 mm / 3.75 g catalogue specification, 1.3 mm thickness, inscriptions, orientation and catalogue identifiers. No Numista or PCGS photograph, valuation table, logo or catalogue prose is reproduced.
Data rule: official institutional specifications take priority. Annual mintages are retained as Numista secondary catalogue figures unless an official year-specific total is independently verified. The absence of a 1928 row is recorded as an absence in the supplied secondary table, not converted into an unsupported official zero.