Japan Commemoratives issued during the period of 50yen postal rate for domestic cover (1) Block of 4, Comb cancellation

I know covers are needed to show the usage of the stamps in traditional philately, howeve I'm collecting used stamps as well just because it's fun for me. First I decided to complete all the used stamps in block of 4 with comb cancellations some day. It's not so easy as well as difficult. I have some but not complete.
Shown left is a block of 4 of Japan 1977 commemorative of 50th anniv. of ham radio with comb cancellation of November 25,1977  Ogaki post office.There is a possibitily for this block to be used on non-postal usage, howeve it is still beautiful with comb cancelation.



Even though I'm focusing only on the used stamps with comb cancellation,  I found the used stamps with the other cancellations such as roller cancellation and get it also.Of course it's more interesting when I organize a collection with some trial version of such cancellations used during 1970's, I have to study more from now on.
Left shown is a block of four of Japan 1978 Human Rights commemorative with Arakawa post office Dec.22, 1978. TBecause this stamp was issued on December, it's more difficult to get used stamps of the issued year than the other stamps.
But on the other points of view, if the commemoratives used just after the issue, more possibility of postal usage has come, so the date is also important.



It improves the collection if I were to get a used stamps cancelled by some interesting post office.
Left shown is a block of 4 of 1980 Congress of IGU&ICA with comb cancellation of Sep.5th, 1980. The post office is rather unique and it shows Tennoji following Annex of Japan Savings Office.
I think this alone is not enough, but after completing it, I can persue more interesting items.