Keichō Chōgin: The Starting Point of the Edo Silver Coin System
Keichō Chōgin (慶長丁銀) is the first official silver coin of the Edo Shogunate, which began minting in Keichō 6 (1601) when Tokugawa Ieyasu achieved the unification of Japan. As the origin of a total of 10 types of Chōgin coins that followed, including Genroku, Hōei, and Tenpō, it boasts the highest standards in terms of fineness, design, and weight. Its shape is a result of the “fukiya method,” where a craftsman pours molten silver into a sand mold and shapes it into a sea cucumber form with both hands. The slightly varying contours of each piece continue to fascinate collectors today. The standard weight is roughly 130–160g, but there are also larger pieces exceeding 150g and smaller pieces around 100g, offering diversity characteristic of weighted currency. Keichō Chōgin not only functioned as the foundation of the unified currency system of the Edo Shogunate but also serves as evidence of the advanced silver refining techniques of the time. For an overview of Edo silver coins, please refer to the Edo Silver (Chōgin & Mameitagin) Introduction.
Silver Fineness 80%: Its Meaning and Verification Methods
A prominent feature of Keichō Chōgin is its high fineness of approximately 80% silver (Permanent Exhibition Catalog of the Currency Museum). This is the highest value among the 10 types of Chōgin from the Edo period, and when contrasted with the decline in fineness due to later re-minting, its value stands out. The remaining approximately 20% of components are primarily copper, an alloy designed to harden the silver and enhance durability. Viewing Keichō Chōgin from its cross-section reveals a consistent silvery white metal layer, visually indicating its high fineness. In contrast, Genroku Chōgin (about 64%) and Tenpō Chōgin (about 26%) tend to have a yellowish hue due to increased copper content, enabling rough era determination by color alone. Using XRF (X-ray fluorescence analysis) allows for the accurate, non-destructive measurement of fineness. When utilizing expert appraisal services, requesting this analysis data can greatly improve purchasing decision accuracy. For general methods of authenticity judgment, please also refer to the Guide to Identifying Fakes and Alterations.
Types and Placement of Kokuin: Stamps Proving Authenticity
The Kokuin (極印) stamped on Keichō Chōgin is a crucial piece of evidence proving its authenticity and era. The main Kokuin can be classified into three types. Firstly, the “Jōze” (常是) mark. This oval stamp shows the Gosumitsuki (official approval) of the silver mint’s highest authority, Gotō Shōzaburō, and is often stamped relatively large and clear on Keichō Chōgin. Secondly, the “Gin” stamp. The rectangle frame with the kanji 銀 indicates the casting official, and there could be multiple stamps. Thirdly, the “Character Mark” indicating the era and fineness, with characters like 長, 慶, and 保, making it possible to estimate the minting period through their combinations. The more clear and numerous the Kokuin, the higher the evaluation. Conversely, if some are missing or unclear, it results in depreciation. Additionally, there are fake Kokuin (後銘) added in later periods, so the depth, font, and edge sharpness of the Kokuin need to be judged comprehensively by experts. It is essential to understand Grading Standards for Old Coins for such appraisals.
The Number in Existence and Market Scarcity: Estimating the Issuance Volume
The exact number of Keichō Chōgin issued is unknown, with various opinions among researchers. However, many were collected and melted down during later re-minting, making existing Keichō Chōgin particularly scarce among all Chōgin. It is estimated that about 10–20 pieces of Keichō Chōgin appear in major domestic old coin auctions annually. This is significantly fewer compared to the dozens of Tenpō Chōgin and Ansei Chōgin that appear around the same time, which is a major factor supporting market prices due to scarcity. The approach to collecting rare old coins with low issuance numbers tends to see increased demand from overseas collectors (especially in Europe, America, and Southeast Asia), and during periods of yen depreciation, international bidding becomes active, often resulting in auction prices exceeding domestic levels.
Market Price Realities: From Average Condition to Extremely Fine Condition
The market price of Keichō Chōgin varies greatly depending on the condition and state of its Kokuin. Our auction database does not yet have verified records of Keichō Chōgin itself. Therefore, price ranges by condition will not be presented until we have verified records (we adhere to a policy of only listing source-cited records in market reports). Notably, when a piece weighing over 150g, called “Large Keichō Chōgin,” appears on the market, the competition tends to be fierce among collectors due to the higher silver content. The policy is to list only the auction records that can be confirmed with sources as market reports. For the optimal exit strategy at the time of sale, please refer to Introduction and Utilization of Old Coin Auctions. Keichō Chōgin is not highly liquid, so it is important to conceptualize it as a long-term investment with an assumed holding period of 3–5 years.
Combination with Mameitagin: The Added Value of Set Items
Keichō Chōgin, when preserved alongside the simultaneously minted “Keichō Mameitagin (慶長豆板銀),” receives a much higher evaluation than when alone. Mameitagin are small silver ingots used for fractional and small-scale transactions, serving as historical evidence of how Chōgin and Mameitagin were used in commercial transactions at the time. If a combination set from the same era remains with the original container (paulownia box, straw wrapping, etc.), additional antique value is added. Particularly, items accompanied by certificates or documents believed to have been used by merchants in the Keichō era are recognized for academic value and may be donated to museums. For detailed information about Mameitagin, refer to Explanation of Mameitagin. For an overall explanation of Chōgin, please see The World of Chōgin.
Practical Authenticity Judgment: Common Forgery Patterns in Keichō Chōgin
Due to the high market value of Keichō Chōgin, forgeries and alterations have historically circulated. Here are the main forgery patterns and how to identify them. 【Later Cast Items】“Replica Chōgin” made during the Meiji and Taishō periods are sometimes aged to appear genuine. Identification involves examining the texture of cast marks and the aging pattern of the silver color. Authentic Keichō Chōgin exhibits distinctive 400-year-old sulfurization patterns. 【Fineness Alteration Items】Items surface-plated with silver with interiors made of copper, lead, tin, or other metals. It can be detected through XRF analysis or specific gravity measurement (compared to pure silver's specific gravity of 10.49). 【Kokuin Replacement】Items where the Kokuin of Keichō was added later onto the silver base of Ansei Chōgin. Be cautious if the Kokuin's depth and the silver base's texture do not match. To detect these forgeries, it is strongly recommended to obtain a certificate issued by a regular member of the Japan Numismatic Dealers Association. It is extremely risky for beginners to make judgments on their own.
Appropriate Storage Methods: Long-term Preservation of High-Fineness Silver
Keichō Chōgin, with its 80% silver fineness, tarnishes relatively quickly when exposed to sulfur and moisture in the air. However, properly stored pieces can maintain excellent condition for over 400 years, as demonstrated by existing examples of Keichō Chōgin. The ideal storage environment is a stable atmosphere with relative humidity below 40% and temperature between 15–20°C. For individual storage, use 'acid-free' Mylar flips or coin capsules and seal them in airtight metal cans with silica gel desiccant. Do not use PVC vinyl flips, as the chemical reaction with silver leads to discoloration. Natural aging toning (darkening) over time may be valued as historical evidence, but artificial polishing or cleaning significantly reduces market value. For high-value pieces like Keichō Chōgin, avoid any cleaning or maintenance without consulting experts. Refer to Proper Storage Methods for Old Coins for storage basics.
Sources and Points of Caution When Purchasing
When purchasing Keichō Chōgin, selecting a highly reliable source is paramount. Recommended purchase routes are prioritized as follows. Firstly, major specialized auctions (e.g., Tokyo Classical Association, Kosenkai-organized auctions). Before bidding, you can confirm the physical item, and an appraisal has been conducted before listing. Secondly, regular member stores of the Japan Numismatic Dealers Association. Members have gone through rigorous screening, significantly reducing the risk of acquiring forgeries. Thirdly, major overseas auctions (e.g., Heritage Auctions, Stack’s). Reliable listings are prevalent in major auctioneers with specialized Japanese coin departments, but consider shipping and customs costs. Purchasing through flea market apps or online auctions presents extremely high authenticity risks and is not recommended. There is always a reason for a 'Keichō Chōgin that's too cheap.' Detailed guidance on appraisal and assessment before purchase is explained in the Guide to Obtaining and Buying Old Coins.