The foreign settlements in Japan were basically identical to the concessions ("sokai" in Japanese) founded in the treaty ports of China around the same period; as a result, the concessions in China were also generally referred to in Japan as "foreign settlements" until the 1920s.
同時期に中国各地の開港場に設置された租界と基本的には同じであり、日本では1920年代頃まで中国における租界も一般的に「居留地」と呼んでいた。