If you're already shopping at Muji, may I recommend their Passport memo book? It's the same size and dimensions as a passport (and by default comes in Japanese

If you're already shopping at Muji, may I recommend their Passport memo book? It's the same size and dimensions as a passport (and by default comes in Japanese passport red), which makes it the perfect size for a (male) jean pocket. I always carry one and an astronaut pen. https://www.muji.us/products/passport-memo-9s62?variant=40011518673086 https://www.muji.us/products/passport-memo-9s62?variant=4001...