In the 16th century, gold and silver coins were minted following active mine developments by feudal warlords. Oda Nobunaga fixed the exchange rates between gold, silver and copper coins, and Toyotomi Hideyoshi ordered the mintage of gold and silver coins, including Tensho Oban gold coins. Tokugawa Ieyasu increased his control over gold and silver mines, secured mintage technology and systems, and issued Keicho silver and gold coins in 1601. The Tokugawa Shogunate government subsequently issued Kan'ei Tsuho copper coins, within the process of establishing a unified monetary system called the “tri-metallic monetary system,” based on gold, silver and copper coins. The tri-metallic monetary system was significant because it was a unique monetary system based on the standardized currencies introduced by the central government. The tri-metallic monetary system was a relaxed unification system, which allowed local feudal lords to issue currencies other than the three standardized ones, such as clan notes to be circulated within their territories.
In the latter half of the 18th century, the demand for small-denomination currency increased due to expanded production of commercial crops in local villages. The Tokugawa Shogunate government issued silver coins (Meiwa Nanryo Nishu-gin <2-shu-gin>) with denominations based on gold coin units. Thus, the silver coins eventually became supplementary currencies of gold coins.
Toward the end of the Edo period, recoinages (Bunsei and Tenpo recoinages) were often carried out to finance the budget deficits of the Shogunate government, which led to chronic inflation.
From the middle to late 16th century Disruption of the inflow of coins from China and the appearance of gold and silver coins

In the latter half of the 16th century, the inflow of Chinese coins was disrupted, leading to a decrease in the circulation of coins 4). In the 1570s in western Japan, rice was used instead of coins to settle large transactions like real estate. Warlords actively developed mines, and minted silver and gold coins for large transactions and for military funds, including Sekishu-gin silver coins and Koshu-kin gold coins.
At the Iwami silver mine, a new refining technology known as “cupellation” was introduced ahead of other mines in Japan. The silver produced from this mine was exported overseas.
The Koshu-kin gold coins were issued based on the currency units ryo, bu and shu, adopting the quaternary numeral system, and these units continued to be used for gold coins during the Edo period.
4) Chinese coinage:
In the 16th century, silver coins played an exclusive role in Chinese coinage and the production of privately, as well as officially, minted coins was stopped, which led to a suspension of the outflow of Chinese coins to Japan.
Latter half of the 16th century Spreading use of gold and silver coins

Oda Nobunaga and Toyotomi Hideyoshi aimed to establish a monetary system as a means to exercise control over the whole nation. Nobunaga issued an order to prohibit coin selecting (erizeni). In the order, he mandated the use of gold and silver coins for transactions of expensive goods, and fixed their exchange rates against copper coins. Hideyoshi took over direct control of mines throughout the country and minted the standard coins, including Tensho Oban gold coins.
Oban gold coins were used in ceremonies as rewards or gifts among samurai families. These practices lead gold coins to gain official currency status.
17th Century Unification of gold, silver and copper coins

Tokugawa Ieyasu placed the mines under his direct control and promoted the improvement of the mintage technology for the establishment of gold and silver mints known as “kobanza” and “ginza.” In 1601, he issued Keicho gold and silver coins minted in standardized types, fineness and shapes. Regarding copper coins, although those circulated before the Edo period had been used for some time, Kan’ei Tsuho was minted in 1636 to ensure a stable supply. Initially, the Tokugawa Shogunate government commissioned the mintage of these coins to copper mints (“zeniza”) across the country with fixed-term licenses.
The Tokugawa Shogunate government issued gold, silver and copper coins as forms of currency that held independent value. Gold coins (Koban, Ichibu-kin, etc.) were issued as currencies with denomination, while silver coins (Cho-gin, Mameita-gin, etc.) were issued as currencies by weight. As for copper coins, one coin was denominated as one mon.
Official exchange rate: 1ryo of gold = 50 monme of silver = 4,000 mon of copper
Gold coin (Koban): 1 ryo = 4 bu = 16 shu
Silver coin: 1 monme (≒3.75g) = 10 fun,
1,000 monme=1kan
Copper coin: 1,000 mon = 1 kanmon
17th century Appearance of paper money and circulation of clan notes (hansatsu)

Around the year 1600, a priest and merchant in the Ise Yamada area (present day, Mie prefecture) issued the Yamada Hagaki check as a deposit receipt for small change to be paid in exchange for silver coins traded by weight, and this check was circulated as currency in the local area. Subsequently, merchants mainly in the Kinki area began to issue private checks, and the clans mainly in western Japan also began to issue hansatsu notes as a means to finance their deficits and cover the shortage of small-denomination currency issued by the government.
In order to circulate standardized coins all over the country, the Tokugawa Shogunate government endeavored to prevent the circulation of hansatsu notes by prohibiting their use, granting fixed-terms for issuing licenses, or by limiting the type that could be used to only the silver denomination type. However, these measures proved to be ineffective.
At the end of the Edo period, nearly 80% of the clans had issued hansatsu notes, resulting in severe inflation. Due to the shortage of small-denomination currency, hansatsu notes issued by powerful merchants under the commission of clans were circulated even beyond the clan boundaries.
From the end of 17th century to the first half of the 18th century Genroku and Hoei recoinages

The Tokugawa Shogunate government carried out recoinages (Genroku recoinage in 1695, Hoei recoinage from 1706 to 1711) to debase gold and silver coins in order to increase the money in circulation and to improve the government’s fiscal situation. These measures brought a large amount of seigniorage to the government, but the increased money circulation caused inflation.
The government established recoinage offices, inviting workers from gold and silver mints. After the Genroku recoinage, the kobanza gold mint began to be called kinza.
Official exchange rate: 1 ryo of gold = 60 monme of silver = 4,000 mon of copper
First half of the 18th century Shotoku and Kyoho recoinages

To cope with inflation caused by the Genroku recoinage, another recoinage (Shotoku regoinage) was carried out in 1714 to increase the gold fineness according to a proposal made by Arai Hakuseki, a Confucian adviser to the Shogun. The fineness of Shotoku Koban gold coins was set at the same level as Keicho Koban gold coins of the early 17th century. This resulted in a sharp reduction of money in circulation, causing stagnancy in economic activities and a decline in commodity prices.
The government, however, further increased the fineness of Kyoho Koban gold coins in 1715, the year after the Shotoku recoinage.
Of all recoinages that were carried out in the Edo period, only the Shotoku and Kyoho recoinages resulted in increased gold and silver fineness.
Middle of the 18th century Genbun recoinage

The Tokugawa Shogunate government conducted yet another recoinage (Genbun recoinage; debasement of gold and silver coins) in 1736 to deal with a drop in rice prices caused by the Shotoku and Kyoho recoinages through increasing the circulation of gold and silver coins. This resulted in improvement in the economic condition. The Genbun Koban gold coins continued to be circulated stably for the next 80 years.
The Genbun recoinage, or the debasement of high-quality Shotoku gold and silver coins, was conducted not to increase the government's income, but to solve social problems.
In the Genbun era of the Edo period, many copper coins were minted within a short period of time. After the mintage of the Kan'ei Tsuho iron coin in 1739, the use of iron coins became mainstream. In the middle of the 18th century, in order to control the amount of circulation of these coins, the government began to permit their mintage only in those mints that were under the government's supervision.
Middle of the 18th century to the 19th century Appearance of silver coins with denominations

In 1765, the Tokugawa Shogunate government issued silver coins with fixed weight (Meiwa Gomonme-gin <5 monme-gin> silver coins) to be exchanged at an official exchange rate of 1-ryo of gold for 60 monme of silver, and subsequently in 1772, issued Meiwa Nanryo Nishu-gin silver coins with denominations based on gold coin units. The government promoted the use of the coins by proactively making loans to moneychangers (ryogaesho), and in the first half of the 19th century, silver coins with denominations were circulated all over the country.
The Gomonme-gin silver coin carried the fixed denomination of “5 monme,” and moneychangers, who had been earning profits from fluctuations of exchange rates in the market, strongly objected to use these coins.
On the obverse of the Meiwa Nanryo Nishu-gin silver coin, it was indicated that eight Nanryo Nishugin silver coins could be exchanged for one 1-ryo Koban gold coin. In line with the government’s policy, the coins began to be circulated widely as supplementary currencies of Koban gold coins, since it was more convenient to use silver coins with denominations rather than those traded by weight.
In 1768, the Kan’ei Tsuho Yonmon (4 mon)-sen brass coin was minted, which carried a wave pattern on the back. From the end of the Edo period to the Meiji period, Yonmonsen iron coins were also minted in large numbers.
First half of the 19th century Bunsei and Tenpo recoinages

The Tokugawa Shogunate government carried out the Bunsei and Tenpo recoinages in 1818 and 1832, respectively, to debase the gold and silver coins in order to compensate for fiscal deficits.Official exchange rate was set at 1 ryo of gold = 60 monme of silver = 6,500 mon of copper.
The recoinages, however, caused confusion in the monetary system and increased commodity prices. The government also minted Tenpo Tsuho Hyakumon (100 mon)-sen and Tenpo Goryo (5 ryo)-ban coins to cover fiscal deficits.
The Tenpo Tsuho 100-mon-sen coins (1835) were minted in large numbers; however, the amount of material used for the mintage of each of these coins was almost the same as that used in five and a half Kan’ei Tsuho 1-mon-sen coins, which caused chronic rises in commodity prices.
The amount of gold contained in one Tenpo 5-ryo-ban (1837) coin was equivalent to the total amount of gold contained in four and a half of the 1-ryo Tenpo Koban gold coins. This new, low-quality coin was badly received among the people, and the mintage was soon suspended.