Beautifully Bound booklet 5 and 10
After the two outstanding books ”Beautifully Bound” number 1 and 2 (aka the ”black book” and the ”red book”), a series of booklets were started: ”Beautifully Bound” numbers 3–11.
These were published by Tenseisya, Abeno Osaka
I am not certain about the order of publication, but this should be issue number 5 (1965) and number 10 (1966).

See earlier posts here:
https://kinbakubooks.wordpress.com/2013/09/10/beautifully-bound-booklet-series/
And here:
https://kinbakubooks.wordpress.com/2014/02/20/beautifully-bound-4-1965/