Japanese Shu: Rectangular Silver Coins of the Edo Period

Illustrated Specimen Details: 1 Shu (Japan)

Example Specimen: 1 shu, 1853-1865 (Japan — Edo Shogunate)

The Era of Emperor Kōmei: This rectangular silver coin was minted during the reign of Emperor Kōmei (1846-1867), the 121st Emperor of Japan. It represents the Kaei Isshugin type, a characteristic silver currency of the late Edo period.

Calligraphy & Authentication: The vertical inscription 一 朱 銀 translates to "One shu silver". To guarantee its quality, the coin bears an incuse stamp with the hieroglyph 定 (Jo), confirming that the silver content matches its face value.

Mint Authority: The markings 常銀 (Ginza) indicate the Silver Mint, the official place where silver bullions were traded and struck. The name 是座 (Jōze) refers to the hereditary controller of the mint who supervised the production.

1. JAPAN (17th-19th centuries): shu = 250 mon = 1/4 bu = 1/16 ryō.

About the name of the coin shu: The name comes from the term "朱" (zhu), which means cinnabar (one of the oldest mineral paints: the main component — mercury sulfide).

According to another version, the name comes from the Chinese measure of weight zhu (later: an ancient Chinese coin) — an old measure of weight equal to the weight of 100 grains of millet.

Japanese Shu: Geometry of the Edo Period

The shu was a vital fractional unit within the remarkably complex monetary system of the Tokugawa Shogunate. Unlike the round coins common in the West, Japanese gold and silver denominations of this era were often rectangular, reflecting a traditional aesthetic and a focus on weight-based value.

The Triple Currency System

Pre-modern Japan operated on a "Sanpō" (three-metal) system where gold, silver, and copper circulated simultaneously. The shu acted as a bridge in merchant accounting, helping navigate the exchange between gold ryō and copper mon.

Rectangular Design & Craftsmanship

The rectangular shape of the silver 1 shu is a hallmark of Japanese numismatics. These pieces were not just currency but official shogunal documents in metal, featuring sophisticated calligraphy and "Ginza" mint marks that protected the economy from forgery.

The End of an Era

With the Meiji Restoration in 1868, Japan moved toward westernization. The complex system of shu, bu, and ryō was replaced by the decimal yen. Today, these rectangular pieces are highly prized by collectors for their unique shape and the historical weight they carry from the time of the Samurai.

Key Point

The shu was a unique rectangular fractional coin, traditionally equal to 1/4 bu. It represents the sophistication of the Edo-period economy, where precious metal weight and shogunal authority met in a distinct geometric form.

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