monopoly

Japan had banned exchanges with foreign countries as a national policy.
It called Sakoku.

Well，there were exceptions to Sakoku.
Tokugawa had continued to trade with China and the Netherlands at Nagasaki of their territory in Kyushu Island.

Nagasaki is at the west end of Japan.
At the time of the 16th century，Western sailboat had come well to Kyushu Island under the influence of ocean currents maybe.
And they brought great wealth to the lords of this land.

”Do not pass wealth to their.”

Sakoku policy had also the meaning of monopoly of foreign trade by Tokugawa in order to maintain their power.
It was abolished.
It was supposed to be a good thing also for another lords.
　
・・・・・・・・・

By the way, Japanese at that time did not know well Japan history.

People at the time, especially samurai and reading class of common people.
It would might be feel funny to you，”History” for them，it meant the history of China.

Classic that they need to learn, it was classic of China.
Japanese ones were thought under that.　
(Maybe, Latin is feeling important.)　
　
"Sakoku is policy from the ancient Japan."　
"Tokugawa had abandoned the policy of our ancestors have been protecting."
　
Some people thought so.
One of them was the Emperor in Kyoto.　
　
・・・・・・・・・　
　
"Reverence to the true king"　
　
This thought also came over from China had been popularized in Japan at that time.　
The Emperor was the presence of only authority. (there was no power)
However，for this reason, reverence to the Emperor was common to Japanese at that time.　
Later，this thought became the ideological basis to overthrow "fake king" Tokugawa.