社会保障協定（しゃかいほしょうきょうてい）とは／What is a social security agreement?- Background and purposes

As various kinds of international exchanges become more frequent, the number of people detached to work abroad or people living abroad after retirement is increasing every year. When working abroad, you must be enrolled in the social security system of the country you are working in, and occasionally you are obliged to pay contributions to both countries. On the other hand, to be eligible for the pension benefits under the system of each country, you may need to be covered by the system for a certain length of period. Accordingly, you may not be eligible for benefits even if you contribute to the system because you did not satisfy the coverage period requirements.
Social security agreements are concluded for the following purposes:

• To avoid "dual burden of contribution payments" by arranging your compulsory coverage between two countries. (Elimination of dual coverage)
• To enable you to totalize your periods of both Japan and the other country to fill the gap for benefits under the system of the agreement country so that you may qualify for benefits. (Totalization of coverage periods)