1976 Philatelic Ad Postcard From Japan- Interesting Cancel

Found this little beauty amongst a hodge podge. Not sure of value of stamps or card or cancels but love the use of card for selling japan stamps. Any additional info appreciated. I know I've seen a few japan covers go for really high sums but don't have the knowledge on the country to have a clue.

Edited title - Interesting the way they calculate based on emperors reign. The 7 cent (or equivelant to cents in japan) stamp is actually backed with what looks like another card. I would assume that is re use of an uncancelled stamp without taking the time to soak it off its originating pc. Guess glue sticks are international.

Nitrolures, could you rotate the cachet on the front of the card right way up please, and perhaps give a closer scan. I developed a very sore neck trying to read the inscription on the pillar.

I ask because this looks rather curious. The town name in the big red cachet is Machida, and the only Machida I can find in my Japanese gazetteer is in Tokyo, but Hirakata is in Osaka.

If not big enough I will rescan tommorow. Thought maybe that cancel was of a philatelic nature but its tied to main card stamp- possible used twice?

After a bit of head-scratching, I worked out the Japanese inscription. It reads 'Historical marker: Takasaka Stone Age remains'. I tried Googling the Japanese, but couldn't find anything useful. In fact, the only place I found the entire Japanese phrase was in an online Japanese-English dictionary!

Given the different dates on the cachet on the 20 Yen stamp, and the others, I'd say the card has been reused: first time, in Tokyo; second time. for mail to Canada.