Claiming pension from another country

I am from the UK, a permanent resident in Japan and have been paying in to the Japanese pension system for 15 years now. I am planning to retire outside of Japan, but before the standard retirement age. Will I still be able to draw my Japan pension from when I am 65, even if I am living in another country by then? Or will I need to technically remain a resident of Japan until I am 65? Thanks!

Considering a Japanese national can receive his pension even after getting citizenship of another country, you will be able to receive it as a non-Japanese who resides outside of Japan.

https://www.town.taka.lg.jp/category_guide/detail/id=17920
Ｑ２）外国籍になっても任意加入は続けられますか？
Ａ２）国籍がなくなると、外国に居住している間は、国民年金に任意加入できなくなります。受給資格期間（１０年以上）を満たしていれば外国籍になっても年金は受けられます。

Here is information for claiming the pension benefit in English.
https://www.pfa.or.jp/english/deferred/howto/index.html