Japanese Type Set Winding Down... Looking For Some History Now

Wikipedia has a lot of good info, but there are some holes and inconsistencies:

1) If the Yen was authorized in July 1871, why were they made in circulation quantities in 1870? Were these technically just patterns? Also, what was the conversion rate between the Tokugawa coinage and Yen? I know that they were legal tender until the 1870s, but when was the cutoff?

2) Was the 5 sen coin redesigned in 1871 due to the apparent striking issues, or for unrelated reasons?

3) Why were no coins produced at all in 1872?

4) Is there any significance in the shift from square scales to V scales on base metal coins in 1877? Also, why does every catalog ignore the existence of the wide rim vs. narrow rim 1 rin coin?

5) What's the deal with years where only like 80 coins were produced in each denomination?

6) Were the redesigns in the 1930s a direct result of rising militant fascism, or just coincidental?

7) How many months was the 1938 bronze "crow" sen produced? All three designs (Crest, Crown bronze, Crow aluminum) seem to be common with large mintages, so I am guessing something like 6-8 months?

8) What exactly was the conversion rate from JPY to USD between August 1945 and the passing of Bretton Woods? The yen was set at about 1/3 of a US cent by 1950, but that doesn't make sense for a coinage series that still had a 0.05 yen coin.

Fairly basic questions that I have not been able to find an answer to.

1) If the Yen was authorized in July 1871, why were they made in circulation quantities in 1870? Were these technically just patterns? Also, what was the conversion rate between the Tokugawa coinage and Yen? I know that they were legal tender until the 1870s, but when was the cutoff?

The M3(1870) yen coins were meant to be used as Trade dollars.
The others I guess are like the euro coins minted 1999-2001.

According to Japanese Wikipedia:
Conversion rate was 4000 mon = 16 shu = 4 bu = 1 ryo = 1 yen = 1.5g pure gold.
Exchangeable Until M21(1888) for gold/silver, M29(1896) for others.



2) Was the 5 sen coin redesigned in 1871 due to the apparent striking issues, or for unrelated reasons?

Yes, striking issues with the dragon.


3) Why were no coins produced at all in 1872?

There are gold coins dated M5(1872)
Some coins were produced in 1872 dated M4(1871)


4) Is there any significance in the shift from square scales to V scales on base metal coins in 1877? Also, why does every catalog ignore the existence of the wide rim vs. narrow rim 1 rin coin?

There does not appear to be much significance in the change to V scales.
Regarding the 1 rin coins, the JNDA catalog only states that there exist coins with non standard diameters.
"Because the manufacturing process differed from that of other coins."


5) What's the deal with years where only like 80 coins were produced in each denomination?
To give as gifts. (According to Japanese Wikipedia...)


6) Were the redesigns in the 1930s a direct result of rising militant fascism, or just coincidental?

Which design? The brass Crow sen design was chosen from designs entered by the public.
The crow is Yatagarasu (https://en.wikipedia.org/wiki/Three..._crow#Japan)
By itself it is no more fascist than the badge of Japan's national soccer team.
However under different circumstances the design may have been less nationalistic.

7) How many months was the 1938 bronze "crow" sen produced? All three designs (Crest, Crown bronze, Crow aluminum) seem to be common with large mintages, so I am guessing something like 6-8 months?

I don't know the start date, but they switched to aluminium after a change in the
law on June 1st. My guess is 5 months from January - May.
BTW These are brass (90% copper, 10% zinc), not bronze. Brass contains no tin.


8) What exactly was the conversion rate from JPY to USD between August 1945 and the passing of Bretton Woods? The yen was set at about 1/3 of a US cent by 1950, but that doesn't make sense for a coinage series that still had a 0.05 yen coin.

According to this article, initially 5-10 yen per dollar, then pegged at 15.
https://news.google.com/newspapers?...392509&hl=en

But if you were in Hong Kong and had been forced to accept military monopoly money, then it was worthless.
On 6 September 1945, the Japanese Ministry of Finance announced that all military yen became void. Overnight the military yen literally became useless pieces of paper.
https://en.wikipedia.org/wiki/Japan...r_redemption

I see why you say that about this coin:
http://en.numista.com/catalogue/pieces13956.html

Pure nickel 5 sen, 1933-1938
1. New design at the beginning of the occupation of Manchuria
2. An emergency reserve of nickel
3. Sun rays
4. The bird is a golden kite (https://en.wikipedia.org/wiki/Order...Golden_Kite)



The 1938 sen, I forgot about the paulownia sen and misread the text.

1. Old (pawlonia) design: 87.6 million
This was made until about June 1st, presumably for 5 months from January-May.

2. Brass Yatagarasu design: 113.6 million

This was made starting on or soon after June 1st, the date of the revisions to the law.

3. Aluminum Yatagarasu design: 45.5 million
The text says, in a rather literal translation: Since copper was getting hard to procure, after the law changed they soon switched to aluminium.
Meaning they made the brass coins for a short while, but were soon forced to ditch copper altogether.

I can't find the production period of the brass coins.
Maybe they just decided to use up all the planchets that had been made, instead of melting them down.

Reference: page 90 of this (Japan Mint history, in Japanese):
http://www.mint.go.jp/wp-content/up...df/ayumi.pdf