an oval gold coin

"1 ryō(両) is the price of rice of 1 koku(石).
It seems defined so on early in the Tokugawa regime."
A little while ago，I read such a sentence in blog.
　

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When Kinjirō came here.
At that time，Annual tribute was 1005 bales and 127 ryō.　
And Annual tribute of 100 years ago was 3100 bales and 200 ryō.

Of course Annual tribute was paid in rice.
And Annual tribute to the field crops was paid in money as an exception.

Most of the breakdown of 127 ryō and 200 ryō.
Probably it was Annual tribute from the field crops.


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By the way，1 koku is 10 to(斗) about 180 liters.
180 liters ≒180 kg.

Current price of rice 5 kg at Japan.
It is about $ 20.
In short, Price of rice 180 kg is $ 720.

Although can not be a simple comparison，therefore 1 ryō is about $ 720.
It is possible to estimate that way.

However，I have calculated at 1 ryō $ 1,000 until now.
($ 1¥ 100)

"1 ryō was about ¥ 100,000."
Because I often read a description like this.

"Difference of its $ 280.
In short、Value of rice was higher than now.
Price of rice was reduced by technological innovation of modern."
I thought so.


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Incidentally 1ryō was a gold coin.　
It called "Koban".（小判）

This gold coin was present before the Tokugawa regime.
But its size was not constant.
It was used after the weighing by balance every time.

"The weight of Koban is 4,76 monme.(匁)
The content of gold in Koban is 86,79%."
Tokugawa regime was defined so.

1 monme is about 3,75g.

3,75×4,76＝17,85
17，85×0,8679＝15,492015

And I examine the price of gold bullion at Japan today.
(2013/06/05 16:47・Japan time)
　
The price of 1g is about ￥4552.
4552×15,492015＝70519,65228
　
In short,1 ryō is about $ 705.
　
When the analogy from the price of rice，1 ryō is about $ 720.
When the analogy from the price of gold bullion，1 ryō is about $ 705.
　
Balance of gold and rice of then and now
It was about the same.