Vintage wallet / check book with beautiful wave art

Vintage wallet / check book with beautiful wave art and some Asian writing inside. I’m not sure if it’s Japanese, Chinese or something else. If you can read please let me know what it says! My dad may have gotten on one of his trips to Taiwan for all I know. Anyways it’s an interesting material, almost a silky thick paper like texture. It does show some minor wear and discoloration so check the photos carefully please.