Hi Peter
No, my definition of coin does not gold and silver bars. These are usually made by private companies not national issuing authorities and do not circulate from hand to hand as money: it is a bit difficult to get change for a 400-ounce good delivery gold bar at your local corner shop! Modern bullion coins, and the smaller gold and silver bars are stores of wealth using the imperishable nature of the value of the metal they contain and do not form part of the circulating money/currency of any nation, except in so far as they can be used to back fiduciary note issues. It would, as you say, not include tokens like the Canadian bank tokens: the operative word there is 'tokens', they were private issues accepted in lieu of government issued coins because there weren't any.
If I can cover your points in order:
1 The isshu-gin/ nibu-kin type coins definitely circulated within Japan as money.
2 They (like most money) could act as a store of wealth but their main use was to facilitate the purchase of goods and services.
3 The weight standards are closely maintained within the different issues, and the officially declared mintage of the 1837-54 issue of isshu-gin was 78,916,556 and the 1853-1865 ibu-gin 159,244,800 for instance, so I think they can be said to be available in an 'appropriate quantity'.
4 The denomination is clearly stated on each of the coins, isshu-gin='1 shu silver' for instance. The fact that different issues could have different weights and finenesses but still retain the same stated denomination emphasizes the fact that they are coins, subject to inflationary processes, but still coins.
One of my main sources is Hartill's new 'Coins of Japan' (for the denominations and the fineness of different issues). The mintage figures come from the JNDA catalogue. I also take the evidence of the Bank of Japan website (quoted below) which makes it clear that the Tokugawa government issued the isshu-gin and nibu-kin types intending them to circulate as coin.
The koban was as you say issued in fairly large quantities (17,435,711 for the Gembun (1736-1818) issue for instance). The fact that these 17 million plus coins were struck in the period 1736-1818 when foreign trade was essentially forbidden I regard as proof that they *did* circulate as coin inside Japan and could not have been intended as a ‘sop to foreigners’ who would not have had access to them. Their current rarity is mainly due to the fact that the Japanese valuation of silver and gold was very different to the Western valuation (5-1 in Japan, 15-1 in Europe and America) which meant that once Japan had been ‘opened up’ to trade with the West vast amounts of gold haemorrhaged out of Japan in a few years in exchange for silver, and was simply melted. The koban were not used to 'pay off foreigners', the foreigners took advantage of the difference in gold/silver ratio to bleed the gold coinage out of Japan. As soon as the Shogunate realised this they revalued the koban against the silver coinage by reducing the fineness and weight, but even this didn’t solve the problem as the value of the silver coins against the Mexican dollar was also unfavourable (the Americans insisted on an exchange rate of 3 Tempo ichibu-gin to the Mexican dollar when the real exchange rate should have been 2 Ansei nisshu-gin). See
http://www.imes.boj.or.jp/cm/english/history/18C/ (on the Bank of Japan website) for an explanation of how the foreign traders took advantage of the exchange rate differences.
I would like to see the Keynes article but I think he has got it as much wrong as Carson.
The oban coinage was certainly mainly a ceremonial coinage, and struck in correspondingly low numbers (16,565 for the Keicho oban, 1601-c.1650, and just 1,887 for the Tenpo oban, 1838-1860 for instance), but the kobans, shus and bus were issued in a definite value relationship intended by the government of the time to circulate within the country as money, and I think that is the essence of a ‘coin’.
There were two different types of silver ‘money’, the bullion cho-gin and mamieta-gin, and the coin silver, such as the isshu-gin and ichibu-gin. Both were issued in parallel up to 1865 when the bullion issues ceased.
I have great respect for Carson as a numismatist, but I think that in the case of his comments on Japanese coins in general he has oversimplified things. Re-reading the paragraph you quoted his comments on the bullion nature of the cho-gin and mameita-gin are totally correct. However, his comment puts the mameita-gin into a ‘second category’ when in fact they were an integral part of the exchange mechanism, the major part of the transaction being paid for by the chogin whilst the final ‘topping-up’ to the final price was done with the mameita-gin. The over-simplification is further evidenced by his comment in the next paragraph where he refers to the ‘kanei tsuho (Pl. 1013) which was produced from 1626 until 1863 with four characters on the obverse and wave-like lines on the reverse.’ The ‘kanei’ mon were produced by private contractors from 1626-1636 when the government took over production. These were then produced until 1867 with blank reverses or one or two character mintmarks. The wave-like markings on the reverse don’t come in until 1768 when four-mon coins were issued with these markings, continuing until 1869.
What the 1869 banking law did was to replace the Japanese native style coins with Western round coins: it didn't create coinage in Japan.
Alan