Amazon.com : Maruman Loose Leaf Binder "Giuris" A5 20 Rings Beige F290-21 : Office Products

These are the best ones that I was able to find earlier this year. In the end though, I just bought a bunch of b5 paper and got a japanese one for daily use.

https://www.amazon.com/gp/product/B09NPN8XGG/ref=ox\_sc\_saved\_title\_9?smid=A28ZKYI2GX8H30&th=1