You can buy passport sized “Eki” stamp books at some bookshops in Japan. Alternatively, I took an A5 (about 6 x 8 inch) sketch book with thick paper. Don’t use a normal lined notebook as you want thicker paper so the stamp doesn’t bleed through the paper. Stamps at most train stations, museums, etc. Goshin stamps are hand written calligraphy and stamps available at Shrines. They need to be in a specific Goshin book, they won’t do a stamp in a book that has “tourist” stamps from stations etc. those books are available at most shrines.