Japan 1964 commemorative 100 yen

y#79 - https://en.numista.com/catalogue/pieces9584.html

Non-circulating with 80 million mintage? You gotta be kidding me.

This mintage is higher than most of the years for the regular 100 yen (y#78). Same size, weight, and composition, too.

You'd be surprised, its a very common issue, if anything not less than a few million.