I wouldn't consider China to be isolationist, because China's history is full of foreign interaction. The reason China fell back and lost the Opium Wars was no

I wouldn't consider China to be isolationist, because China's history is full of foreign interaction. The reason China fell back and lost the Opium Wars was not due to isolationism, but rather because for some other reason(s), they missed out on the industrial revolution. But the exact reasons(s) they missed out on the industrial revolution is a great debate, and is the quadrillion dollar question...