tiny old cast metal elephant, incense burner? mini animal figurine vintage Japan

Tiny little metal elephant with a hinged lid 'saddle' on its back... I think maybe this is an incense burner for those little incense cones?

I can't think what else could possibly fit in such a small opening, I think it's too small to have held a pencil sharpener. The whole piece measures just about 2 1/2" x 2 1/2" overall

It's early to mid-century vintage at our best guess, marked Japan on the bottom. The casting is remarkably detailed. Original finish is rubbed and worn. It's a lucky elephant, with trunk up!