---
title: "Kaei Isshugin: Value, Authentication and Market Price Guide"
url: "https://ittendo.com/en/coinpedia/edo-silver-012-kaei-isshugin"
site: "ITTENDO"
type: "coinpedia"
category: "edo-silver"
series: "Edo Silver Coins"
lang: "en"
---
# Kaei Isshugin: Value, Authentication and Market Price Guide

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Individual prices are listed only once verifiably matched, sourced records exist.

- 時代: 江戸
- 素材: 銀
- 額面: 朱
- 発行量: 通常
- 価格帯: 普及

## Overview and Historical Background of the Ka'ei Isshugin

The Ka'ei Isshugin is a small denomination silver coin issued by the Edo shogunate starting in Ka'ei 6 (1853). It is extremely small and rectangular, measuring approximately 10mm by 8mm, with a face value equivalent to one shū (1/32 of a ryō). This coin was issued in the same year that Commodore Matthew Perry's Black Ships arrived at Uraga, representing a major turning point in Japanese history. As such, it stands as a witness to the political and economic turmoil of the Bakumatsu period.

The Ka'ei Isshugin is the second generation of Isshugin, following the Bunsei Isshugin which began minting in Bunsei 3 (1820), and circulated until the currency reformation by the Meiji government in Meiji 2 (1869). A detailed explanation of the overall system of Edo silver currency is available in [Introduction to Edo Silver Coinage (Chōgin and Mameitasugin)](/coinpedia/edo-silver-001-overview).

## Comparison with Bunsei Isshugin: Decline in Silver Purity Reflecting Financial Difficulties of Bakumatsu

The most notable feature of the Ka'ei Isshugin is its extremely low silver purity. While its predecessor, the Bunsei Isshugin, had a silver purity of about 25%, the Ka'ei Isshugin's purity dropped to about 23.8%. The remaining approximately 76% is an alloy primarily composed of copper, making it a low-purity alloy coin in name only. This decline in silver purity starkly reflects the fiscal distress of the shogunate leading up to the Bakumatsu period.

Following the signing of the Treaty of Peace and Amity between Japan and the United States (Ansei 1, 1854), the opening of Japan caused severe disruptions in the country's monetary system. The difference in the domestic and international gold-silver ratio (domestic 1:5 vs. international 1:15) led to a massive outflow of gold overseas, forcing the shogunate to resort to lowering coin purity to secure financial resources. Despite its lower silver purity, the historical background gives such coins considerable collectible value.

## Basic Specifications and Physical Characteristics: Key Numerical Data for Identification

The basic specifications of the Ka'ei Isshugin are as follows: it weighs approximately 0.87g (with a tolerance of ±0.05g), is rectangular with dimensions of about 10mm by 8mm, and has a silver purity of about 23.8% (with a copper content of approximately 76.2%). The obverse is inscribed with 「一朱銀」 and a paulownia crest, while the reverse bears the inscription 「銀座」 along with a date stamp.

Holding it in your palm, you will be surprised by its small size. Compared to a modern 10 yen coin (with a diameter of 23.5mm), its area is less than a quarter. Due to its diminutive size, care must be taken to prevent loss or damage during storage. Additionally, due to its high copper content, it is prone to verdigris forming on the surface if not stored properly. For specific methods on long-term preservation, refer to [Proper Storage Methods for Old Coins](/coinpedia/basics-006-hokan). The precision of the inscriptions and the clarity of the paulownia crest are critical points for condition evaluation.

## Authenticity Assessment and Identification Points: How to Distinguish from Similar Items

While the Ka'ei Isshugin is relatively inexpensive, making it less prone to sophisticated forgery, care must be taken to not confuse it with the Bunsei Isshugin or modern reproductions. There are three main points of identification.

First is the weight. The standard weight is about 0.87g, and coins under 0.78g or over 0.96g measured by a precise scale (0.01g units) should be treated with caution. Second is verifying the inscriptions. The 「一朱銀」 on the obverse should be clear, with particular emphasis on the unique Edo Ginza character styling of 「朱」. Third is checking the Ginza stamp and the date engraving on the reverse. Confirmation of the Ka'ei-specific mint marks distinguishes it from the Bunsei Isshugin. Observing the color tone is also effective; the Ka'ei Isshugin, with its higher copper content, tends to appear slightly redder than the Bunsei Isshugin. For comprehensive methods to identify fakes and similar products, refer to [Complete Guide to Distinguishing Fakes and Processed Items](/coinpedia/basics-004-fakes).

## Market Value and Price Range: Approximate Trends Based on Condition

The market price of the Ka'ei Isshugin varies significantly based on its condition. Circulated goods with unreadable inscriptions (fair condition) are priced around 300 to 800 yen.

Compared to the Ichibugin (Tempō to Ansei) or Nishugin, the trading price is lower, but its value as a "real historical document" that survived the turmoil of the Bakumatsu period is not insignificant. For a comprehensive understanding of the value of old coins, [Factors Determining the Value of Old Coins](/coinpedia/basics-001-value-drivers) is a useful reference. Acquiring items individually with careful inspection of condition rather than bulk purchases is more likely to yield quality coins.

Individual prices are listed only once verifiably matched, sourced records exist.

## Position in the Edo Small Denomination Silver Coin System

To properly understand the Ka'ei Isshugin, it is essential to grasp the system of small denomination silver coins in the Edo period. By the late Edo period, smaller units below one ryō, such as Ichibugin (1/4 ryō), Nishugin (1/8 ryō), and Isshugin (1/16 ryō), circulated alongside each other. As the smallest denomination silver coin, the Ka'ei Isshugin was a practical currency used in everyday small transactions by the common people.

The conversion relation was one ryō = four Ichibugin = eight Nishugin = sixteen Isshugin, and a detailed explanation on Nishugin can be found at [Types and Market Trends of Nishugin](/coinpedia/edo-silver-005-nishugin). The co-circulation of multiple types of small denomination silver coins vividly demonstrates the economic complexity and diversification of the monetary system during the Bakumatsu period. Similar to a modern 10 yen coin, Isshugin played a crucial role in supporting the everyday economy during the late Edo period. This topic is further discussed within the context of the broader [Introduction to Edo Silver Coinage (Chōgin and Mameitasugin)](/coinpedia/edo-silver-001-overview).

## Economic Turmoil in the Bakumatsu Period and the Monetary Significance of the Ka'ei Isshugin

The 16 years in which the Ka'ei Isshugin was in circulation, from Ka'ei 6 (1853) to Meiji 2 (1869), coincided entirely with the historic upheaval of the Tokugawa shogunate's collapse and the Meiji Restoration. Events such as Perry's arrival (Ka'ei 6), the signing of the U.S.-Japan Treaty of Amity and Commerce (Ansei 5, 1858), and the Kan'ei coinage reform (Man'en 1, 1860) all dealt decisive blows to Japan's monetary system.

Particularly after the opening of the country, the gold-silver ratio crisis was severe, resulting in a massive outflow of domestic gold, prompting the shogunate to adopt the desperate measure of drastically reducing the gold content in Koban in Man'en 1. Details of this currency reform are explained in [The Value and Market Trends of Man'en Koban](/coinpedia/edo-gold-007-manen-koban). Amidst this upheaval, the Ka'ei Isshugin continued to support the base of the commoners' economy. Until abolished during the establishment of a modern currency system by the new Meiji government, it carved an important page in Japan's currency history as a "silver coin that survived the Bakumatsu period."

## Starting a Collection and Acquisition Methods

The Ka'ei Isshugin is relatively affordable and accessible, making it suitable as an entry point into Edo silver coin collections. Primary sources for acquisition include sales events at numismatic specialty shops, numismatic auctions, and online platforms like Yahoo! Auctions. Due to its low price range, it is also suitable for beginners to practice gaining auction experience, allowing for an inexpensive cycle of bidding, winning, and condition evaluation.

Before purchasing, be sure to check the clarity of inscriptions, the presence of verdigris, and any edge chips in photos in advance. Furthermore, given its extremely small size, ensuring packaging that considers the risk of loss during transport is important. Consultation and purchase through a trusted numismatist can be referred to [Guide to Sources and Purchase Methods of Old Coins](/coinpedia/basics-008-shotai). Basic knowledge for participating in auctions is detailed in [Introduction and Practical Use of Numismatic Auctions](/coinpedia/basics-007-auction). The Ka'ei Isshugin is a unique collectible that allows you to tangibly experience the dramatic turning point in Japanese history found in the Bakumatsu period.