in 1736, again lowering the gold content of the koban. One ryō was also considered equivalent to 1 koku of rice, or the amount of rice needed to feed one person for one year, although this was a less exact standard, which fluctuated depending on the abundance of the rice crop in any particular year. On June 27, 1871, with the introduction of currency reforms after the Meiji Restoration, the ryō was abolished, and replaced one-for-one with the Yen. Modern conversion These fluctuations in the gold content of the koban over time, as well as differences in the cost of living between various points in the Edo period and in modern times make any attempt to relate the value of one ryō in terms of modern currency very difficult. Japanese middle school textbooks often state that one ryō was approximately equivalent to 100,000 Yen at the start of the Edo period, and around 3000–4000 yen at the end of the Edo period. On the other hand, the Currency Museum of the Bank of Japan states that one ryō had a nominal value equivalent 300,000–400,000 yen, but was worth only 120,000–130,000 yen in practice, or 40,000 yen in terms of rice. See also Koban (coin) Tael (两, liǎng) in Chinese Japanese mon (currency) Wadōkaichin References Lucassen, Jan. Wages and Currency: Global Comparisons from Antiquity to the Twentieth Century. Peter Lang (2007), Ohnuki, Mari, "The Genroku, Hoei, Shotoku, Kyoho, and Gembun Koban", Short Essays on Monetary History Contained in Monetary and Economic Studies, Research Division 3, Institute for Monetary and Economic Studies, Bank of Japan (ed.), Monetary and Economic Studies, 15.2 (1997). Honjo, Eijiro, "The Economic thought in Tokugawa days", Kyoto University Economic Review, vol. xiii, no. 1 (Kyoto, Oct. 1938), p. 1–22. [Overview of the period 1600 to 1867] Economy of feudal Japan Modern obsolete currencies