---
title: "Keicho Koban"
url: "https://ittendo.com/en/coinpedia/edo-gold-009-keicho-koban"
site: "ITTENDO"
type: "coinpedia"
category: "edo-gold"
series: "Edo Gold Coins"
lang: "en"
---
# Keicho Koban

> Conclusion: Keicho Koban is the first high-purity gold coin of the Edo Shogunate, representing the pinnacle of collection with both historical value and investment appeal.

- 時代: 江戸
- 素材: 金
- 額面: 両 / 分 / 朱
- 発行量: 通常
- 価格帯: 普及

## The Background and Historical Significance of the Keichō Koban

The Keichō Koban was first minted in the 6th year of the Keichō era (1601) under the orders of Tokugawa Ieyasu, who had achieved the unification of the nation. It was the first official koban issued by the Edo shogunate, and its historical significance is immeasurable. Ieyasu aimed to unify the chaotic currency system of the Sengoku period and establish a nationwide monetary system.

For this important enterprise, Ieyasu appointed Gotō Shōzaburō Mitsumasa as the head of the Kinza. The Keichō Koban is a high-purity gold coin (the museum catalog lists 84% fineness and 18 g; prescribed and measured values form multiple series that cannot be merged into one figure — see the [Complete Record](/en/record/keicho-koban)). This high purity was an important measure to demonstrate the authority of the new shogunate both domestically and internationally and to establish trust in the currency among the people.

The minting of the Keichō Koban laid the foundation for the monetary system of the Edo period that lasted for about 260 years. It greatly contributed to the stabilization of economic activities and left a firm footprint in Japan's economic history. To understand the history of Edo gold coins, this [Introduction to Edo Gold Coins (Koban & Ōban)](/coinpedia/edo-gold-001-overview) is an indispensable reference.

## Physical Characteristics and Design of the Keichō Koban

On the surface of the Keichō Koban, the mark "壹両" is boldly engraved in the center. Below it, the kaō of Gotō Mitsumasa, the head of the Kinza, is beautifully stamped within a fan-shaped frame. This kaō is an extremely important point for authenticating the koban.

The obverse carries horizontal striations called gozame struck across the surface (research literature treats these as an obverse feature). Measured specimens (9 coins held by the Bank of Japan IMES) are 69.8–73.5 mm long and 38.1–39.2 mm wide, larger than koban of later periods. When held, its solid weight is unmistakable.

Due to its high gold purity, the Keichō Koban presents a rich, beautiful golden color. Especially those minted in the early period, called "early period," were crafted with great care, and many still vividly retain the engraving. No definitive record of mintage or surviving population has been confirmed.

## Gold Purity and Weight: The Core of Value

The Keichō Koban's fineness and weight form multiple value series. The museum catalog lists 84% fineness and 18 g (rounded); the kinza document standard is 84.29% (early), with sources recording a later rise to 86.8% (the "mimashi" standard); measured specimens (9 coins, Bank of Japan) run 83.6–86.5% gold and 17.70–17.75 g. These cannot be merged into a single "true" figure — see the [Complete Record](/en/record/keicho-koban) for the full series and sources.

We do not compute gold content or bullion value from unconfirmed single figures. The Keichō Koban's value rests on its character as an art piece that tells history, not merely on precious metal.

Measured specimens are oval, 69.8–73.5 mm by 38.1–39.2 mm, and their heft is instantly felt when held. Details of the production system (minting sites, etc.) will be added to the Complete Record as sources are confirmed. These minute characteristics become [Factors that Determine the Value of Old Coins](/coinpedia/basics-001-value-drivers), making expert appraisal important.

## Tokugawa Ieyasu's Currency Unification Policy and Economic Influence

The background behind the issuance of the Keichō Koban involved Tokugawa Ieyasu's strong sense of national duty to unify the chaotic currency system of the Sengoku period. At that time, Japan experienced a proliferation of region-specific gold coins with varying purities, such as Kōshū gold and Suruga gold, which posed significant barriers to commercial transactions. This lack of unified currency led to economic stagnation and hindered nationwide commercial development.

Ieyasu positioned the issuance of a unified currency as one of the essential power bases for establishing national control. The Keichō Koban played a role in standardizing commercial economies through currency unification, promoting smooth circulation under shogunate governance. This energized nationwide economic activity and helped form a stable societal foundation.

Furthermore, the Keichō Koban served not only as an economic tool but also functioned as the "stamp of the nation," symbolizing the authority of the shogunate. This forward-thinking concept of Ieyasu laid the groundwork for the Edo monetary system for the next 260 years, significantly establishing the very concept of the koban. The unified monetary system was an indispensable element for the economic development of the Edo period.

## Key Points of Authentication: Examination of Stamps and Kaō

When determining the authenticity of a Keichō Koban, one important point to inspect is the details of Gotō Mitsumasa's kaō. This kaō naturally expresses the way lines are drawn, angles, and the subtlety of pressure, elements that forgers find most challenging to reproduce. Experienced appraisers can sense the unique vitality of authenticity from these fine penmanship details.

Next to verify is the style of the "壹両" inscription on the surface. Attempts have been made to date pieces by differences in script and striking, but dating by appearance remains a research hypothesis. The gozame striations and their wear can serve as a basis for confirming natural aging.

For appraisals, it is recommended to check the color tone of the koban under natural light rather than fluorescent light. Additionally, it is essential to use a high-magnification loupe of 20x or more to carefully examine the details of the stamps and kaō. Minor scratches, processing marks, or unnatural luster may indicate signs of forgery. Referencing [Complete Guide to Identifying Fakes & Altered Items](/coinpedia/basics-004-fakes) alongside provides a comprehensive perspective for careful judgment.

## Comparative Analysis of the Keichō Koban and Successor Koban

Comparing the Keichō Koban with successor koban, its overwhelming high purity stands out. Throughout the Edo period, the gold purity of koban was frequently reformed due to the shogunate's financial situation. For example, the [Genroku Koban](/coinpedia/edo-gold-005-genroku-koban) issued in the 8th year of the Genroku era (1695) had a gold purity plummeting to 57% (catalog; 57.37% in the prescribed-standard series) compared to the roughly 84% (catalog) of the Keichō Koban. This difference is a notable 27 points or so, meaning a substantial reduction in actual gold content.

On the other hand, the [Kyōhō Koban](/coinpedia/edo-gold-010-kyoho-koban) issued in 1715 (catalog) achieved an exceptional high purity of 86.8% (prescribed-standard series), surpassing the Keichō Koban. This was a temporary recovery to Keichō Koban's level as a measure to raise coinage quality, proposed by Arai Hakuseki. However, compared to the late-period Ansei Koban (gold purity 56.8%, weight 8.97g), the Keichō Koban reaches a level nearly triple its gold content (a rough calculation from the rounded catalog values).

Thus, in the history of Edo currency, the Keichō Koban holds an unshakable position as the "pinnacle" due to its high purity and substantial weight. Through comparison with other koban, a clearer understanding of the historical and economic value of the Keichō Koban becomes possible. Learning about the [Types of Koban and Price Ranges](/coinpedia/edo-gold-002-koban-types) helps deeply understand its transition and value shifts.

## Risks and Measures Against Counterfeits and Forged Items

Due to the high value of the Keichō Koban, it has been counterfeited as a type of private minting since the Edo period, and even today, numerous expertly forged replicas circulate. Special attention is needed for those "modified" to resemble Keichō Koban by plating lower-grade koban like the Genroku Koban with gold. Some cases are extremely difficult to distinguish based solely on appearance, leading even seasoned collectors to err in judgments.

One powerful tool for verification is measuring gold purity through X-ray fluorescence analysis — though matching measurements alone cannot prove authenticity. This allows for accurately identifying differences in alloy ratios that are indiscernible to the naked eye. However, conducting such analysis individually is challenging; therefore, utmost care is necessary during purchase. ITTENDO recommends purchasing pieces with JNDA (Japan Numismatic Dealers' Association) certificates or from trusted specialized dealers.

Internet auctions and flea market apps, while handy, present a particularly high risk for counterfeits and forgeries. Always consider that inexpensive items usually have underlying issues and avoid hasty purchases. Acquiring professional knowledge, with reference to the [Guide to Identifying Fakes & Altered Items](/guide/fake-detection), is the first step to protecting valuable assets.

## Assessment and Market Price of Keichō Koban in the Collectible Market

The Keichō Koban receives extremely high evaluations from collectors due to its historical value as the first koban of the Edo shogunate. Our auction database does not yet contain any record verifiably matched to the Keichō Koban itself. We do not present price bands until verified matches exist — per the [Complete Record](/en/record/keicho-koban), only sourced records are listed.

No definitive record of mintage or surviving population has been confirmed. For market activity, see our verified market records.

Due to limited circulation volume in the market, finding a piece in the desired condition requires time and patience. However, given its rarity and historical background, acquiring one ensures it becomes a central part of a collection. Understanding the [Study of Old Coin Market Cycles](/coinpedia/basics-005-market-cycles) can help in determining the optimal timing for purchases.