There is this online shop that sells many beautiful Japanese paper products and books called Uguisu that you must see! In fact, the moment I found it my jaw dropped and I felt as though I'd entered Japanese crafty heaven. You simply must spend some time today clicking around this gorgeous website and bonus! It's all in English! Yay!
Uguisu stocks things that are either designed or made in Japan (or both) and they carry books, stationery, paper balloons, linens, craft supplies (like masking tape in pretty colors), magazines and many other inspirational products that you are sure to enjoy. Hiki, the shop owner, is based in Japan but don't worry - she ships globally and has built up a cult following online because her service is great and her products are so well curated. Have fun!