For non-Japanese who contribute Japanese Pension (Kosei Nenkin / Kokumin Nenkin) AFTER APRIL 2021, maximum period of pension refunds (Lump-sum Withdrawal Payments) is extended up to 5 years (60 months).
For non-Japanese who end their contributions of Japanese Pension (Kosei Nenkin / Kokumin Nenkin) BEFORE APRIL 2021, maximum period of pension refunds (Lump-sum Withdrawal Payments) is 3 years (36 months), that is unchanged.
Note: Pension refund (Lump-sum Withdrawal Payments) can be claimed by non-Japanese who contribute Japanese Pension (Kosei Nenkin / Kokumin Nenkin) for more than 6 months AND less than 10 years (120 months).
For details please see this article:
https://www.youat-jp.com/pensiontopics_detail_e.php?id=13
Website of Japan Pension Service (Japanese):
https://www.nenkin.go.jp/service/jukyu/sonota-kyufu/dattai-ichiji/20150406.html