Why was Japan called a recluse (outside) nation?

1)       Japan, a nation located to the far-east of Asia, is widely known as the "Land of rising sun'.
2)       The Portuguese, the Spanish and the Dutch people had been more or less involved in business with Japan from the 16th Century.
3)       As these people tried to spread Christianity in Japan, they were expelled (barred).
4)       Japan became a self-centered (selfish) nation.
5)       The doors of Japan had been closed for the European nations for one hundred and fifty years.

6)       As a result, Japan was known as a recluse (hermit) nation.