[Presumably it should read '...the day before you became a Japanese citizen or permanent resident...']If you become a naturalized Japanese citizen or if you are admitted as permanent resident before you become 65 years old, your overseas residence period between April 1, 1961 and the previous day you become Japanese citizen, within your age between 20-59, will be considered as “complementary period”. The complementary period is the valid period to be included to see if you satisfy the 10-year period requirement to be entitled to the Old-age Basic Pension. However, this period is not considered in benefit amounts calculation.
https://www.nenkin.go.jp/pamphlet/kokun ... nglish.pdf
The source is an English-language pamphlet about kokumin nenkin on the nenkin.go.jp site, yet the main English page of nenkin.go.jp doesn't mention this exception. Has anyone seen this 'complementary period' cited in other sources? Or benefited from it? Or think they might benefit from it?