The Ansei Koban is an important gold coin indicating a turning point in Japan's monetary system at the end of the Edo period. Minting began in 1859 by the Edo Shogunate as a response to gold outflow.
What is the Ansei Koban?
The Ansei Koban is a gold coin minted by the Edo Shogunate during the late Edo period, with production starting in 1859. During this time, Japan faced pressures to open its borders following Commodore Perry's arrival, which forced the country into participating on the international stage. Particularly due to the Treaty of Amity and Commerce signed with the United States in 1858, preparations were made for the opening of major ports in Yokohama, Nagasaki, and Hakodate the following year. Amid such circumstances, the Shogunate was compelled to review its currency system, leading to the minting of the Ansei Koban.
The Ansei Koban was created as part of the Shogunate's recasting efforts to counteract gold outflows, but ultimately, it became the last minted in the traditional Koban size. The gold fineness was 56.8%, nearly identical to that of its predecessor, the Tenpō Koban (天保小判), but its weight was significantly reduced to 8.97 grams. This recasting was merely a temporary measure against the gold outflow crisis, and the following year saw the introduction of the Man'en Koban (万延小判), which was even smaller and had lower gold content. The Ansei Koban is regarded as a vital gold coin symbolizing a turning point in the Japanese monetary system before the port openings.
The Ansei Koban has an elliptical shape, approximately 52mm long and 30mm wide, and is notably smaller than the Tenpō Koban. The obverse features the inscription "壹两" and the "Mitsutsugu" (光次) seal of the Gotō family, while the reverse bears the "正" stamp, crucial for ensuring authenticity. The "正" character serves as an important feature for authenticating its genuineness. Moreover, due to a short minting period of about one year, the total number minted was small, and the circulation volume was limited, resulting in observable individual differences. These features make the Ansei Koban a historical witness to the turbulent political and monetary confusions of the late Edo period.
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Historical Background of the Ansei Koban and Its Impact on Evaluation
The Ansei Koban is a coin deeply linked to the foreign crises of the late Edo period, reflecting the agonizing decisions made by the Shogunate. With the gold fineness set at 56.8%, nearly identical to that of the Tenpō Koban, the Ansei Koban was lightened significantly to approximately 8.97g from the Tenpō Koban's 11.2g. This reduction meant that each Ansei Koban contained only about 5.1g of pure gold, indicating a decrease in the actual value of the coin.
Behind this reduction was not just a financial crisis but a significant disparity in the gold-to-silver exchange ratios used in international trade. In Japan, gold and silver were valued at a 1 to 5 ratio, while internationally, gold was valued around 1 to 15 against silver. Exploiting this differential, Western merchants brought large amounts of silver, exchanged it for Japanese gold, and exported it, worsening the "gold outflow problem." The Shogunate attempted to address this by reducing the gold content of the Koban while maintaining its nominal value, but this was only a temporary restraint and failed to completely stop the gold outflow.
The Ansei Koban was the last "old-style Koban" issued by the Edo Shogunate, symbolizing the transition to the Man'en Koban in the following year. The transition in the currency system during this period reflects Japan's economic challenges at the end of the Edo era, and the historical background and characteristics of the Ansei Koban are crucial in understanding Japan's socio-economic conditions at that time. The historical backdrop of the Ansei Koban has greatly influenced its evaluation, marking it as a symbolic currency demonstrating the severity of the gold outflow issue, drawing significant attention among collectors and historians alike.
Moreover, the Man'en Koban that followed was issued the following year, with the gold fineness further reduced. These changes serve as important documents illustrating the economic difficulties and countermeasures faced by Japan at the end of the Edo period. The Ansei Koban continues to carry significance today as a historic coin symbolizing Japan's political and economic challenges during the opening of the country.
Recent Auction Levels in the Edo Gold Coin Category
An analysis of recent auction levels for the entire Edo gold coin category based on specific data reveals that as of September 20, 2026, the median auction price for the past 90 days was ¥6,967, with 2 transactions recorded. In the previous 90 days, the median was ¥40,000 with 5 transactions. However, since transactions are below 10 in each period, the rate of fluctuation cannot be calculated, and the reliability is considered unquantifiable.
In cases where data is limited, the figures obtained are mere indicators, demanding careful analysis for accurate market judgment. Auction examples include a "Niji* Old Coin Koban-shaped Currency" sold for ¥1,033 on September 17, 2026, and a "J*8 One Bu Silver Koban Japanese Edo Old Coin Antique Coin Collection Former Currency Retro" sold for ¥1,300 on September 16, 2026. These instances also suggest a wide range of transaction prices.
To grasp the market trends in detail, referring to past auction histories is effective. Specific price changes and past transaction numbers can be viewed on Check the Price Trend with Market Chart or View Auction Histories. Using such information helps in a more precise understanding of the market trends for the Edo gold coin category.
Factors Dividing the Value of the Ansei Koban
When evaluating the value of the Ansei Koban, especial attention needs to be paid to condition, rarity, and authenticity risks. A critical point in discerning authenticity is the "正" stamp on the reverse. This "正" character is inscribed in a neat Kaisho style, with the balance of the upper "一" and lower "止", the length and angle of the horizontal strokes, and the overall arrangement of the character serving as standards for judgment. Observing the vigor of strokes and smoothness of lines created by skilled artisans is essential.
Additionally, confirming the weight and dimensions of the Ansei Koban is necessary. While the Ansei Koban weighs 8.97g and measures approximately 52mm by 30mm, the Tenpō Koban is 11.2g and about 60mm by 34mm, showing clear differences in weight and size. Particularly, for heavily worn items, visual judgments become difficult, necessitating the use of precise weighing devices and calipers.
Furthermore, the depth of the "壹两" characters and the "Mitsutsugu" seal inscriptions on the surface, and the texture of the woven straw pattern are also important elements in authentication. Due to its short minting period, the Ansei Koban tends to have more individual variations in its woven straw pattern compared to other Kobans. Comprehensive assessment of these features leads to more accurate authentication. For more details on identifying authenticity, refer to How to Differentiate Authenticity.
Records also indicate that the rarity of the Ansei Koban is a significant factor influencing its value. Owing to its short minting period, the Ansei Koban appears to be less common in the market compared to other Edo period Kobans. Consequently, it garners high interest among collectors and historians alike. Combined, these factors position the Ansei Koban as a highly collectible coin with historical significance.
Points to Check When Acquiring and Holding an Ansei Koban
When acquiring or holding an Ansei Koban, extreme caution is necessary to discern counterfeits or altered items. Due to the limited number of Ansei Kobans minted, and thereby small market circulation, issues often arise from "confusion with the Tenpō Koban" or misjudgments from "altered items" rather than outright counterfeits. Especially, since the Ansei Koban and the Tenpō Koban have similar gold purity, it becomes difficult to distinguish by sight in heavily worn or damaged pieces.
To distinguish between Ansei Koban and Tenpō Koban, it's crucial to understand their differences in weight and size. The Ansei Koban weighs 8.97g with an approximate size of 52mm, compared to the Tenpō Koban at 11.2g and about 60mm. Thus, precise weighing and measurement using reliable instruments is necessary to verify these numbers. Additionally, the "正" stamp on the reverse is a decisive identification mark for the Ansei Koban, so ensure to verify it thoroughly.
In the market, sophisticated fakes have been reported, such as adding gold to Man'en Kobans or altering the stamp. These modified counterfeits can be challenging to detect without thorough examination by experts. Therefore, when purchasing an Ansei Koban, it's wise to utilize trustworthy numismatics dealers or appraisal agencies, and if possible, opt for items with certificates of authenticity to mitigate risks. Further information can be found in the Guide to Acquiring and Buying Old Coins.
As the Ansei Koban was issued during a historically significant period at the end of the Edo era, its historical value is reflected in market prices. Its status in the collector's market records significant price fluctuations depending on preservation states. Considering these points, appropriate storage following the Proper Old Coin Storage Methods is recommended when holding an Ansei Koban.
Historical Value of the Ansei Koban and Its Position in the Market
The Ansei Koban is a rare late Edo period gold coin brought about by the pre-opening gold outflow crisis. Its historical background, combined with limited supply, contributes to its premium pricing. Considering the time when it was minted, the Ansei Koban represents a critical period of economic and political change in late Edo Japan, enhancing its value further.
Market records show that the Ansei Koban attracts attention from collectors and investors, resulting in unique trends in transaction numbers and price settings. This market position denotes not just its value as currency but also its role as historical documentation.
The rarity of the Ansei Koban stems from its limited availability, fostering market competition. The combination of rarity and historical value imparts a unique presence compared to other gold coins.
ITTENDO considers continuous observation of the Ansei Koban's market trends crucial, along with understanding how its value changes. Market activity and price fluctuations are directly linked to the fundamental value of the Ansei Koban, understanding of which is important for collectors.
Moreover, utilizing the Vault Price Monitoring for Coins of Interest feature can be beneficial to monitor price trends and market movements. This assists in gaining a deeper understanding of the Ansei Koban's market position.
Thus, through historical value and rarity, the Ansei Koban continues to draw attention in the market. ITTENDO aims to assist in discerning its true value by continuously observing market trends of the Ansei Koban.