Isolationism is a good practice on paper, but when applied it does not work. Many of the problems China faced while under haijin, an isolationism period, included a secluded culture, inability to trade with other countries, and falling behind technologically compared to the rest of the world. Maritime piracy was also a big issue for China, as the few foreign trades they initiated under this period were intercepted by Japanese pirates. Modern nations can definitely learn from this disastrous period as an example of what not to put the country under when regarding foreign relations.
