This is Nekko Dekko, the protector of Honshu.
You’d think it would be easier, painting two pictures on the same piece of paper at the same time. Saves effort stretching it, and all that. But it’s too easy to splatter dark blobs of paint around, and therefore not worth it.
I’m sad that the scanner took out all the delicate gradations of tone in the first picture, and dropped out a lot of the blue altogether.