Anything labeled "origami paper" is fine imo. Diagrams are hard to read at times. It's like doing a puzzle. In high school I made a dragon, and I had to practice making the head alone a few times before I could do it on the actual model. I was going off these literal hand drawn scans from some Vietnamese guy online. I used to do it a lot more, but less so now. Just these cranes at the moment. I'd say medium difficulty is the best I can do. The really advanced stuff is crazy, but I've always wanted to be able to just take a square and make something simple from memory. This crane is all I've got in that regard.