National Pension (support the person's retirement from work) may not be included in calculating old-age, and people in their 20s can contribute.
A pension (/pnn/, from Latin pensio, "payment") is a fund into which a sum of money is added during an employee's employment years and from which payments are drawn to support the person's retirement from work in the form of periodic payments. Periods of non-payment may not be included in calculating the old-age basic pension that the member will receive in the future. People in their 20s can use the contribution postponement system for low-income youth. Category 3  People aged between 20 and 60 years old who are dependent on Category 2 contributors. Contributions are waived for Category 3 members, as their contributions are subsidized by all Category 2 contributors. Category 1  All registered residents of Japan who are aged between 20 and 60 years old, but do not fit into either category 2 or 3 (i.e. typically the unemployed, self-employed, or employees of very small companies). People in this category should go to the National Pension counter at their local municipal office. (People in this category are enrolled in the national health insurance scheme). 
