Recommended storage method
A4 clear file for each theme
If you put them in an A4 clear file for each theme, it is recommended that you can access each idea immediately.
All together in an A4 zipper file
It is recommended to store the A4 clear files that have been sorted into subdivisions together in an A4 zipper file so that the contents can be seen.
You can store it in a bookshelf as a zipper file or put it in your bag and carry it.
A4 zipper files can be purchased at 100 yen shops in Japan.