I have a question about this coin: https://en.numista.com/catalogue/pieces9584.html
It is marked as a non-circulating issue. However, the mintage was 80 million, which is actually more than the typical mintage of the then-current circulating 100 yen coin (which had the same silver content and dimensions as the Olympics commemorative). In fact, in 1964, only 10 million of the standard 100 yen were minted, compared to the 80 million of the commemorative coin.
This article says that the commemorative coin did replace the circulating 100 yen for 1964:
http://coinsweekly.com/index.php?pid=4&id=2723
It seems to me that the Olympics coin was indeed a circulating commemorative. Can anyone confirm? I can put in the change request, but it would be good to have a confirmation from someone who knows for sure.