the new technology

Amount of silver production in Japan was not many originally by the problem of technology.

"1 ： 5～６."
Until the early 16th century,The price ratio at Japan of gold and silver seems to have been it .

But 16th century.
Japan was the Warring States period.
There were many wars in Japan.
Warring States lords ran the mine development for acquisition of war chest actively.

And 1530s，Technician of smelting of Korea has brought to Japan the new technology.
It called Haifuki-hō.(灰吹法)

Production amount of silver has increased dramatically by it.

"１ : 10～13."
As result、Price of silver have fallen to here at the early 17th century.
In short,during the 16th century，The price of silver was in half.
(It was 50 years of late the 16th century in practice.)
　
Japan became a producing district of silver the world's most eminent.
At that time，Output of silver seems to have been about 33％～25% of the world.

"Price of silver of Japan was cheaper than neighboring countries."
This may be natural.

　
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The early 17th century.
Of course，It was the era of the Tokugawa regime already.
Silvers export volume was reached 200,000 kg at the maximum value.(per year)

"Gold 1 = Silver 9,6824073563"
By the way，Exchange rate of Tokugawa was it.
This is less than 10.

Increased production of silver was still going on.

"Gold 1 = Silver 13"
Actual exchange rate at that time was it.
This possibilities is also high.
Probably Tokugawa had set a high price of silver than the market.

But this exchange rate was principle so to speak.
Rate of the market was constantly changing.
　
And probably it was cheaper than the official rate.　
Therefore overseas trade might have been traded by the market rate.
　
However，Japan at that time was taking the closed-door policy.
Overseas trade was limited to part of Nagasaki.　
And Tokugawa had monopolized it.
　
Even the exchange rate of official，it might was cheaper than the other countries.
　
(Just maybe，There was a rate for overseas trade.
I do not know much about foreign trade at that time.）
　
　
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For example.

200,000 kg is 200,000,000 g.

Gold 15、492015g = Silver 150g
Gold 1g was ¥ 4,245.(as of Jun 17, 2013 19:15)
4245×15、492015＝65763,603675

200000000 ÷ 150 = 1333333,33333
1333333,33333 × 65763,603675 = 87684804899,7

Trading of ￥87,684,804,900 at the official rate of Tokugawa.(rounding)