The only other state I can think of which has adopted similar policies is modern-day North Korea, which is also in East Asia
The apparent 'isolationism' of China and Japan has been greatly exaggerated, largely post-hoc by European powers who liked to construe the period before their intervention as one of intentional refusal to engage with the outside world. This section of the FAQ, graciously compiled by /u/ParallelPain (seriously, the amount of work they've done on the Japan FAQ is fantastic), contains answers on various aspects of the topic of sakoku in Japan. I've covered the Qing motives behind establishing the Canton System in a few past answers, but this one is perhaps the most relevant. I haven't had much luck finding past answers on Korea, but this one on attempts at European colonialism in Korea by /u/Cal_Ibre discusses a little bit.