What is Kokan'ei Tsūhō — The Era of Diversity in Early Edo
Kokan'ei Tsūhō (古寛永通宝) is a general term for Kan'ei Tsūhō coins produced from the beginning of their initial minting in Kan'ei 13 (1636) until around the Meireki era (1655–1658). This period is clearly distinct from the later "Shinkan'ei" period and is treated as a separate category in the world of coin collecting. The greatest feature of the Kokan'ei period was the proliferation of privately-run mints across the country, each producing coins with unique scripts, materials, and sizes. In the early Kan'ei period, the shogunate had not yet fully controlled minting, and authorized mints in places like Edo, Kyoto, Sendai, Mito, Tsu, and Nagato Hagi manufactured copper coins with their own patterns (mother coins) and craftsmanship. This situation led to the creation of numerous script variations said to number in the hundreds. The first minting order in Kan'ei 13 was issued by Matsudaira Nobutsuna to the mints in Edo, Kyoto, and Sendai. While initially limited, the rapid expansion of minting locations subsequently spread the diversity of Kokan'ei even further. Understanding this complex minting system is the starting point for collecting and appraising Kokan'ei Tsūhō. For basic knowledge on holed coins, refer to Introduction to Holed Coins.
The Definitive Difference Between Kokan'ei and Shinkan'ei
Kan'ei Tsūhō is broadly classified into "Kokan'ei" and "Shinkan'ei," a dichotomy that holds fundamental importance in collecting. The temporal boundary is marked by the establishment of the government's direct mint, Kameido Mint, in Kanbun 8 (1668). Coins minted after this are called Shinkan'ei, but practically, many consider the Kokan'ei era to have ended with the decline of private mints around the Meireki era (1655–1658). The greatest difference lies in the uniformity of quality. Due to the private nature of minting in Kokan'ei, there are significant variations in script, size, copper quality, and weight. Even coins from the same mint could have slight differences due to the wear of the mother coins or the skill of artisans. In contrast, Shinkan'ei saw progress in standardization under the direct control of the government, resulting in stable quality. The diversity of Kokan'ei adds an element of "treasure hunting for rare scripts" to its collection value. Prices can range from tens of yen to several million yen depending on the script, so keen eyes are crucial for successful collecting. Once you have an overview from The World of Kanei Tsuho, we recommend specializing in collecting Kokan'ei.
Major Scripts and Types — Nisui'ei, Shimayafumi, and Various Schools
The classification of scripts for Kokan'ei Tsūhō has long been debated among coin researchers, with the studies of scholars like Takashi Tanaka often referenced. Here, we explain major scripts popular among collectors. The most renowned rare script is "Nisui'ei (二水永)." It's named for the unique shape of the final stroke of the kanji "永", which spreads like two drops of water, and is thought to have been produced in the early minting sites, mainly Edo. Well-preserved specimens can fetch from several hundred thousand to over a million yen, reigning as the king of rare Kokan'ei. "Shimayafumi (島屋文)" features a script with a strong presence, possessing a unique block-like form resembling an island. It is associated with the Kyoto mint and is a relatively rare script, highly popular. Good examples can be valued from tens of thousands to hundreds of thousands of yen. Other known types include "Nagao'kan," "Mito Coin," and "Matsumoto Coin," each with distinctive regional characteristics. Notably, "Sendai Coin" from the Sendai domain is known for its rough script and is highly regarded among regional collectors. For detailed information on script variations, refer to Detailed Kanei Tsuho Variants.
How to Differentiate Mother Coins and Circulation Coins
In valuing Kokan'ei Tsūhō, distinguishing between mother coins (母銭) and circulation coins is a key point. Mother coins are original coins used to create molds for minting circulation coins, and they are valued significantly higher than circulation coins. Physical characteristics of mother coins include a diameter about 1-2mm larger than circulation coins. The engraving of the characters is deep and clear, and the contour (outer rim) is finely crafted. The surface is smoother than circulation coins, showing a sheen that indicates careful craftsmanship by artisans. They also tend to weigh more than circulation coins. However, appraising mother coins is not easy. Circulation coins in minimally worn and clear condition can sometimes appear similar to mother coins. Additionally, reproductions made in later periods may circulate as mother coins. Key points for appraisal are the overall assessment of the engraving's "depth," "strength," and "uniformity," as no single criterion suffices. Coins identified as mother coins can be valued at tens of thousands to hundreds of thousands of yen, even if the script is the same as an inexpensive circulation coin. Reliable appraisal necessitates consultation with specialized coin grading organizations or experienced coin dealers. Check Fundamentals of Grading for foundational grading standards.
Major Minting Locations and Regional Characteristics
Since Kokan'ei Tsūhō was minted at various mints nationwide, the differences due to minting locations significantly impact identification and valuation. Here, we organize the distinctive features of representative minting locations. Coins minted at Edo Mints (present-day Tokyo) include the earliest Kan'ei Tsūhō and set the standard for script styles, later transitioning to the Kameido and Fukagawa Mints. Early Edo coins are noted for their strong script and comparatively careful finish. Coins from the Sendai domain's mint (present-day Miyagi Prefecture) are known as Sendai Coins, featuring a rough script and distinctive copper quality. Despite being produced in large quantities due to the proximity to copper sources, Sendai Coins have low uniformity in quality and significant script variation. Mints in the Mito domain (present-day Ibaraki Prefecture), Nagato Hagi (present-day Yamaguchi Prefecture), and other domains also produced coins with distinct scripts. Matsumoto Coin (present-day Nagano Prefecture) is renowned for its elegant script, making it popular among collectors. Understanding such regional characteristics forms a crucial knowledge base for Kokan'ei Tsūhō appraisal. Regardless of minting location, acquiring or selling well-preserved Kokan'ei Tsūhō is effectively facilitated by using established coin specialty auctions. Refer to Auction Strategy Guide for guidance.
Market Price Range and Entry into Collecting
The price of Kokan'ei Tsūhō varies widely between tens of yen to several million yen, depending on script, condition, and whether it is a mother coin or a circulation coin. While this breadth poses a challenge for beginners, once critical assessment skills are developed, it offers opportunities to find valuable specimens. General circulation coins (common scripts of mid-grade condition) are typically sold for about 10 to 50 yen, available in bulk from coin dealers or at antique markets. These are ideal for collection practice and script familiarization exercises. Well-preserved circulation coins (high-quality to extremely fine) are valued at approximately 100 to 1,000 yen. For beginners, it is strongly recommended to start by observing inexpensive circulation coins in large numbers to get accustomed to script diversity. Once script identification skills have developed, moving on to collecting rarer specimens is the most efficient step-up. Organize evaluation criteria from Five Factors That Determine Coin Value and avoid unplanned high-cost investments. Individual prices and auction examples are only listed in market records if they are corroborated with verified records (including event, lot, source URL, and confirmation date).
Collection Considerations and Storage Methods
Key considerations for collecting Kokan'ei Tsūhō are as follows. Regarding authenticity issues, rare high-value scripts may have counterfeits circulating in the market. Well-known rare items like "Nisui'ei" are known to have sophisticated reproductions created in later periods. Always confirm with multiple expert opinions and check for the existence of certification before purchase. As for condition assessment, given the nature of copper coins, many show verdigris development due to aging. Regarding verdigris, there are differing perspectives: some view it as "patina from age," while others prefer coins cleaned to pristine condition. Generally, experts do not recommend arbitrary cleaning or chemical treatments, as improper cleaning can damage the surface and significantly reduce value. Confirm criteria for identifying counterfeits and altered items from Introduction to Identifying Counterfeits. For storage, to prevent copper oxidation, use airtight storage containers with regular silica gel replacement. Rare script specimens should benefit from being housed in coin slabs (encased by grading institutions) for value preservation and improved liquidity. Confirm detailed storage guidelines from Storage and Care Methods.