Time to crack open the mattress (new money)

[adamu]

https://www.boj.or.jp/note_tfjgs/note/n_note/index.htm/

[Established]

https://www.boj.or.jp/note_tfjgs/note/n_note/index.htm/

The implications being that old notes will only be accepted up to a certain date?

[adamu]

I thought that would be the first response. But despite the clickbait, I think Japanese banknotes don't expire, you can still use the ancient ones if you like (providing the other party will accept them).

Here's a list of valid past notes
https://www.boj.or.jp/note_tfjgs/note/v ... index.htm/

[Tkydon]

Generally, notes remain legal tender, but merchants will not accept them, so you have to go to the bank to exchange them for new notes of the same denomination.

Of course, older notes may be worth more than face value on the collectors' market...