I’m a Mongolian citizen currently on a travel visa in Japan. Am I allowed to apply for a travel visa directly from Tokyo or must I return home and then apply?
You must apply from Mongolia (or from another country that you have permanent residency). You cannot apply from Japan, as one of the requirements for the visa application is:
Japanese resident card must remain valid for more than 3 months
You can find our more at the official website of the Korean Embassy in Japan.