Using the Japanese razor the proper way is something that you really have to figure out for yourself. There are no manuals like the ones we see in using a western style razor. I'm sure there are some in Japanese but you would need to be fluent to find it and read it. It will depend on how comfortable you are using two hands and how ambidextrous you are. There are some moves that are quite challenging. I've been using one for a while now and still have problems doing a N-S motion on the right side of my neck,I'm left handed.

These razors are actually sharper than western razors because they are asymmetrical so if you use the convex side you are using a side that is less sharp. You can compensate by honing them equally but it still will never be the same. As I've said before if your going to learn to use one you should do it the correct way. To me its the same as someone learning to use a straight but never figuring out how to shave his neck so he finishes with a DE and does that forever.