Diamond
Planet Robot
Maker: Yonezawa

Yonezawa have a unique piece here. Firstly you would
expect a toy of this size to be battery powered, but it's clockwork. (Though
there is a panel on the back clearly indicating a possible battery placement.)
Secondly the shape is utterly unlike anything else: the ears are complex
shell-like structures (in fact, as two sharp eyed collectors noted,
they are the shoulder sockets of the Yonezawa Moon Robot!), the eyeballs
shake about in their frames and the tapering body perches on a pedestal
base. Only the ear antennas are familiar, they're the Robby rings.

This is a rare robot. There are two colour variations: red with blue arms, and blue with red arms. This toy rarely surfaces in the west and when it does it commands a very high price tag.
EXTRA!
Nov 2001: The guess about the battery box was right. There is a prototype battery op version sitting in a Japanese museum.
Thanks to Gernot Muenck for the photo.