Japanese Mon (Tenpō Tsūhō): Value & Cast Coin Guide

Illustrated Specimen Details: Japan 100 Mon (Tenpō Tsūhō)

Example Specimen: 100 Mon, 1835–1870 — Japan (Edo Period)

Design & Inscriptions: This distinctive oval-shaped cast coin with a square central hole is known natively as the Tenpō Tsūhō. The obverse characters read 天保 (Tenpō, the Japanese era name spanning 1830 to 1844) and 通寶 (Tsūhō, meaning "circulating treasure" or "currency"). The reverse displays the denomination 當 百 (equal to one hundred mon). Below the hole is the Kaō—a highly stylized signature or mark used in Japan—belonging to Gotō San'emon, a member of the prominent Gotō family of mint officials descended from Gotō Shozaburo Mitsutsugu (the master metalworker appointed in 1601 to oversee the Edo mint). The edge features two stylized paulownia flowers (individual mint marks known as shirushi).

1. JAPAN (pre-decimalization to 1870): 1 mon = 1 of 250 shu = 1 of 1000 bu = 1 of 4000 ryō. (While some sources trace the first Japanese mon back to 1336, early catalogs frequently list 8th-century cast cash coins under this general denomination format).

Etymology and History of the Japanese Mon

About the name of the coin mon: The mon coin was traditionally marked with the kanji character "文". This exact symbol forms the basis of closely related currencies across East Asia, including the Chinese wén (historically referred to as cash), the Hong Kong wén (or mil), the Korean mun, and the Vietnamese văn. In Japanese economic culture, it remains permanently associated with everyday small change.

Official vs. Illegal Regional Casting: While official records from the legal mints of Edo (modern-day Tokyo) and Osaka state that roughly 485 million 100 mon pieces were issued, historians estimate that underground, illegal regional mints produced an additional 200 million coins. Because these coins were manufactured using sand-casting methods, genuine official issues can be distinguished by their smooth coin fields, whereas counterfeits cast with coarser-grained sand exhibit a noticeably rougher surface. Interestingly, when the currency was eventually demonetized at the turn of the 20th century, the total volume withdrawn actually exceeded the official emission numbers.

Historical Origins and Chinese Influence

The mon served as the foundational low-denomination cash currency of pre-modern Japan, operating as the bedrock of everyday commerce for centuries. Its design was heavily shaped by Chinese monetary traditions; like the standard Chinese cash coin, the typical mon was cast with a round outer shape and a square central hole. For convenient transport and large-scale market transactions, thousands of these coins were commonly strung together on long cords.

The Edo Period and the Famous Kan’ei Tsūhō

Though earlier variants existed before the absolute unification of the country, mon coinage circulated at its highest volume during the Tokugawa shogunate (Edo period). The most iconic and widely recognized variant was the Kan’ei Tsūhō, which featured simple calligraphic inscriptions and circulated in massive numbers. The currency was used universally across feudal Japan by merchants, peasants, urban populations, and samurai alike. During periods of severe domestic metal shortages, the shogunate frequently resorted to casting these coins out of iron instead of copper alloys.

Meiji Restoration and Abolition

The traditional mon system finally came to an end during the rapid Westernization and economic modernization of Japan. Following the Meiji Restoration in the late 19th century, the old complex feudal system was permanently abolished and replaced by the modern decimalized yen currency system. Today, these distinctive East Asian cast coins are highly collectible, with numismatists placing specific value on large denominations, early medieval variants, and unique regional feudal-domain issues.

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