--- title: "Kyōwa Isshu-gin: Value and Authentication Guide — The Highest-Purity Silver Coin of the Late Edo Period" url: "https://ittendo.com/en/article/news-jp-1375-c1dbfc9d" site: "ITTENDO" type: "article" category: "江戸銀貨" published: "2026-09-06T22:00:00Z" source: "一点堂編集部" source_url: "https://ittendo.com/" lang: "en" --- # Kyōwa Isshu-gin: Value and Authentication Guide — The Highest-Purity Silver Coin of the Late Edo Period > The Kyōwa Isshu-gin (享和一朱銀) is a small-denomination silver coin minted by the Edo shogunate in 1802, boasting a silver fineness of approximately 98.7% — the highest standard of the Edo period. Rectangular in shape and measuring approximately 10 mm tall by 5 mm wide, weighing 0.86 g, it bears the inscription「一朱」on the obverse and the Ginza authentication stamp on the reverse. The stark difference in quality compared to the later Kaei Isshu-gin (fineness approximately 26.4%) heavily influences market value, and specimens trade across a price range of roughly ¥3,000 to over ¥30,000 depending on condition. The Kyōwa Isshu-gin (享和一朱銀) is a small-denomination silver coin whose minting began in 1802 under the Edo shogunate. Kyōwa is the era name of the reign of the 11th shogun Tokugawa Ienari (1801–1804), a period that corresponds to the economically mature phase of the late Edo period. As agriculture and cottage industries developed, the need for small-denomination payments in everyday transactions among ordinary people grew, and the isshu-gin played an important role as a subsidiary currency to meet that demand. --- ## What Is the Kyōwa Isshu-gin — The Role and Characteristics of a Late Edo Small-Denomination Silver Coin The Kyōwa Isshu-gin (享和一朱銀) is a small-denomination silver coin whose minting began in 1802 under the Edo shogunate. Kyōwa is the era name of the reign of the 11th shogun Tokugawa Ienari (1801–1804), a period that corresponds to the economically mature phase of the late Edo period. As agriculture and cottage industries developed, the need for small-denomination payments in everyday transactions among ordinary people grew, and the isshu-gin played an important role as a subsidiary currency to meet that demand. Within the monetary system, one isshu represented the smallest unit of metal currency, equivalent to one-sixteenth of one ryō. The Kyōwa Isshu-gin was designed to maintain a high silver fineness of approximately 98.7% while being sized appropriately for small everyday transactions. This maintenance of high purity is itself evidence that the shogunate of the time placed great importance on the credibility of its coinage. In terms of physical characteristics, the Kyōwa Isshu-gin is a small rectangle (tanzaku-gata, or strip shape) measuring approximately 10 mm tall by 5 mm wide, with a weight of approximately 0.86 g. The high silver fineness is reflected in the vivid white lustre of the silver. The obverse bears the inscription「一朱」, and the reverse carries the authentication stamp (gokuīn) of the Ginza. This stamp is a crucial basis for determining authenticity and is an element that must always be verified during appraisal. Because the coin is extremely small, detailed observation with a magnifying glass is indispensable. Continuously issued from the Kyōwa years through the Bunsei period, this coin stands out in terms of quality superiority when compared to the later Kaei Isshu-gin. The Kaei Isshu-gin suffered a substantial decline in silver fineness (against the backdrop of worsening late Edo finances), making the Kyōwa Isshu-gin's high purity its greatest point of differentiation. As a coin that boasts a particularly stable standard of quality within the late Edo silver coinage system, it tends to command a high market evaluation as recorded in the literature. ## The Monetary Policy and Quality Standards of the Late Edo Period as Reflected in the Kyōwa Isshu-gin The silver fineness of approximately 98.7% in the Kyōwa Isshu-gin (享和一朱銀) places it among the highest in the Edo period silver coinage system. This high purity is an expression of the shogunate's policy intention to maintain public trust in its currency. Looking at how silver fineness changed across Edo silver coins, the Keichō silver stood at approximately 80%, the Genroku silver at 64%, and the Hōei silver at 50% — a substantial decline from the early to the middle period. The era in which the Kyōwa Isshu-gin was issued carried on the momentum of the recovery in coin quality that had begun with the Kyōhō reforms. In other words, by maintaining high silver fineness, this coin also retained intrinsic value as bullion. The light weight of 0.86 g reflects the coin's role as the smallest subsidiary currency unit, the isshu. Considering that the ichibu-gin weighed approximately 8.6 g, the isshu-gin maintains a relationship of being one-tenth that weight. This ratio also represented a practical design by which users could intuitively confirm the weight. However, circumstances changed dramatically in the late Edo period. The silver fineness of the Kaei Isshu-gin (嘉永一朱銀, from 1853) declined to approximately 26.4%. Over roughly half a century, the silver fineness fell to less than one-quarter of what it had been; though the nominal value of "one isshu" remained the same, the actual amount of silver contained dropped dramatically. This debasement was an emergency measure to cope with the financial difficulties of the late shogunate period, against the backdrop of the turmoil surrounding the arrival of Commodore Perry. In today's collector market, this difference in quality is clearly reflected in prices. Underpinned by its bullion value due to high silver fineness, the Kyōwa Isshu-gin tends to maintain a stable price level compared to the [Kaei Isshu-gin value and authentication guide](/coinpedia/edo-silver-012-kaei-isshugin). Collecting both side by side offers an excellent opportunity to learn visually and tangibly about the changes in quality across Edo coinage. ## Recent Transaction Levels in the Edo Silver Coin Market For the Edo silver coin category as a whole, the median hammer price over the 90 days up to the reference date of September 7, 2026 was ¥4,650 (38 lots). The 90-day period prior to that recorded ¥3,750 (8 lots); however, because the latter figure is based on fewer than 10 lots, neither the rate of change nor a reliability figure has been calculated. The earlier figure serves only as a reference value for indicating the overall price range of the category. The 38 lots transacted in the most recent 90 days indicates that market interest in Edo silver coins has a certain depth. Looking at actual hammer-price records for the same period, a range of ¥2,800 to ¥16,800 is observed. The highest price was ¥16,800 for a combination of an Ansei mame-ita-gin (両面大黒) and an Ansei ichibu-gin (August 29, 2026), and the lowest was ¥2,800 for an ichibu-gin (August 10, 2026). In the mid-range, multiple transactions in ichibu-gin were recorded, with a tendency to cluster between ¥5,000 and ¥8,500. Specific examples include: an Ansei ichibu-gin at ¥5,500 (August 10, 2026), an ichibu-gin (listed as a historically valuable item) at ¥7,000 (same date), an ichibu-gin (listed as American silver / old coin) at ¥8,500 (August 18, 2026), and a combination of an Ansei ichibu-gin and a Kaei isshu-gin at ¥6,500 (August 10, 2026). These hammer prices are influenced by the mint year, mint location, state of preservation, and the description used in the listing for each individual coin. When reading the market for the Kyōwa Isshu-gin, it is necessary to use the category-wide median of ¥4,650 as a benchmark while also examining the individual factors within the same classification. [Check price trends in the market chart](/market/index), or view detailed transaction records at [see auction history in list form](/auctions). ## Authentication and Value Differences in the Market The single greatest factor influencing the value of the Kyōwa Isshu-gin (享和一朱銀) lies in **distinguishing genuine specimens from fakes**. When confirming the authenticity of this coin, the most important element is the shape and texture of the Ginza authentication stamp (gokuīn) on the reverse. On genuine coins, the stamp is struck to a uniform depth and the flow of metal appears natural, whereas counterfeits and post-production alterations tend to show indistinct stamp outlines or uneven striking depth. The next indicator to verify is the weight. The standard for the Kyōwa Isshu-gin is the light figure of approximately 0.86 g, making confirmation with a precision scale (accurate to 0.01 g) essential. Individual coins that deviate substantially from this figure raise suspicions of confusion with isshu-gin from other periods or of alteration, so it is important to keep a weight confirmation record at the time of acquisition. The dimensions must also be cross-referenced against the standard of approximately 10 mm tall × 5 mm wide. The greatest risk with the Kyōwa Isshu-gin is "confusion with similar contemporary pieces." Identification may be required against isshu-gin from the Shōtoku and Kyōhō periods or from the Bunsei period, and there are subtle differences in stamps and characters among the isshu-gin of each era. In addition to the [guide to authenticating genuine and fake coins](/guide/fake-detection), consultation with specialists and cross-referencing with reference materials is recommended. In the collector market, prices vary greatly depending on condition. Average specimens (those where the weight and stamp can be confirmed) tend to trade at around ¥3,000–¥8,000; fine specimens in good condition throughout may reach ¥10,000–¥20,000; and extremely fine specimens have been recorded trading at over ¥30,000. Highly graded coins (accompanied by a top-rank certificate from a specialist grading service) have in some cases commanded prices that far exceed these benchmarks. On a practical level, because the Kyōwa Isshu-gin is so small in size, particular care is required in handling and storage. Using airtight cases or dedicated coin holders and avoiding direct contact with bare hands directly contributes to maintaining the coin's condition and to preserving its value over the long term. ## The Kyōwa Isshu-gin's Systematic Position and Points to Verify When acquiring or holding the Kyōwa Isshu-gin (享和一朱銀), it is important to understand not only its individual evaluation but also its position within the full scope of Edo-period isshu-gin. The quality of the isshu-gin issued by the Edo shogunate changed with each era, and the transition from the Shōtoku and Kyōhō periods through the Kyōwa period and on to the Kaei period directly reflects the fiscal situation of the late Edo period. The era of the "high-fineness isshu-gin" to which the Kyōwa Isshu-gin belongs functioned as the outcome of the coin-quality improvement policy following the Kyōhō reforms. On the other hand, as fiscal difficulties progressed through the Bunsei and Tenpō periods, currency debasement became unavoidable, and a substantial decline in fineness occurred by the Kaei period. To grasp this progression, it is useful to compare the Kyōwa Isshu-gin with related denominations from the same era, such as the nishu-gin. By consulting [types of old coins and their classification system](/guide/varieties) to confirm where the Kyōwa Isshu-gin sits within the classification framework and what quality relationship it bears to other silver coins of the same period, the historical value of an individual coin becomes clearer. From the perspective of building a collection, the small size of the Kyōwa Isshu-gin offers a practical advantage. Even with limited storage space, it is realistically possible to assemble isshu-gin from multiple eras. Arranging isshu-gin from the Shōtoku period through the Kaei period in chronological order allows one to trace the changes in the late Edo monetary system through actual specimens. At that point, the condition of each individual coin must be managed consistently. By following [proper methods for storing old coins](/guide/storage) and preparing an environment with stable humidity and temperature, the foundation for long-term comparative study is established. At the time of acquisition, recording not only the coin type but also individual differences such as the mint location and the presence or absence of back characters is the first step in building a systematic collection. ## The Position of the Kyōwa Isshu-gin The Kyōwa Isshu-gin (享和一朱銀) is the specimen recording the highest silver fineness of 98.7% among the late Edo isshu-gin. This high quality forms a pronounced contrast when compared with the later Kaei Isshu-gin, and is a factor that generates a rarity premium in the market. Within the limited minting scale of the isshu-gin, the existence of the Kyōwa designation further elevates its scarcity. In the history of silver coin circulation during the Edo period, the transition from the Kyōwa period to the Kaei period was not merely a change of era name but a material turning point characterized by a decline in silver quality. The fact that this transition can be documented in figures for silver content is what makes the Kyōwa Isshu-gin important as a subject of numismatic research. As a collectible, its position is that of an intermediate-level piece that combines accessibility with historical background. It is not a high-end item out of reach for beginners, but nor is it a beginner's piece. When studying the changes in quality across Edo silver coins, the Kyōwa designation holds essential value as a teaching specimen. By following the transaction records circulating in the market, an environment exists in which one can continuously observe what kind of evaluation this single coin receives. At ITTENDO, the Kyōwa Isshu-gin is recorded not merely as a rare item but as an indicator showing the quality standards of late Edo silver coinage.