Taiwan

Taiwan, officially the Republic of China (ROC), is a country in East Asia. The main island of Taiwan, also known as Formosa, lies between the East and South China Seas in the northwestern Pacific Ocean, with the People's Republic of China (PRC) to the northwest, Japan to the northeast, and the Philippines to the south. It has an area of 35,808 square kilometres (13,826 square miles), with mountain ranges dominating the eastern two-thirds and plains in the western third, where its highly urbanized population is concentrated. The combined territories under ROC control consist of 168 islands in total covering 36,193 square kilometres (13,974 square miles). The largest metropolitan area is formed by Taipei (the capital), New Taipei City, and Keelung. With around 23.9 million inhabitants, Taiwan is among the most densely populated countries. [w]

Taiwan and Japan Sign Agreement to Manage Immigration Issues During Crisis

From The Yomiuri Shimbun:

The memorandum will allow Japan to receive information on non-Japanese people who seek entry to Japan from Taiwan, according to the sources. This will help Japan more effectively screen individuals and determine who may pose a threat to domestic security in the wake of a contingency. Under the memorandum, travelers bound for Japan will also receive a pre-departure check at Taiwan airports outside of contingencies.

“Chinese agents could enter Japan by concealing themselves among Taiwanese nationals,” a Japanese source warned.

The article notes how unusual this kind of agreement is and it is kinda chilling that there is public-level planning for this situation. But best to be prepared rather than improvise in the chaos.