Isolation | edo-japan-guide

Why?

At the beginning of the Edo period, Japan was trading with a lot of places like, China, Korea, the Philipines, Thailand, and even Europe.
When Japan built it's first Western-style ship, many European ships started to arrive in Japanese shores.
Tokugawa (he was the shogun at the time) knew that Europeans usually colonize places that they explore and he also didn't want the Japanese people to adopt European beliefs and ideas.
So Tokugawa wanted Japan to be safe and to keep it's power so he closed all of Japan except for Deshima which was the only place foreign ships could come to.

The Sakoku (closed country or period of national isolation) Law ensured stability in culture and power for Japan.
They also became rich (as a country) because they barely traded and hardly had anything to spend the money on.
This decision of isolation made them to move backwards in society. Their weapons, military equipment and technology was not up to date.
They also failed to modernize their government.
When Japan decided to pass the Sakoku Law it seemed like they felt their way of life was the best and everyone else's was inferior to theirs.
They were not open to new religions or new cultures because their leader felt that their way of life was better and he didn’t want his people to get “corrupted”.
When they refused to accept other cultures it lead to them rejecting other ideas, inventions, and resources that could make their lives easier.