Concept artist Tajima Hideki assumed Chikyuu's diameter to be roughly 1/10 of our Earth's. For scale, Honshu will take up almost 1/3 of Chikyuu's surface.
Honshu length: 1300km; Chikyuu d/c: 1725.6km/4007km
…so that made me feel slightly better about the international/continental travel times… (this would open up another can of worms about density/gravity but i digress)
He created the Chikyuu map from a draft by Kamihori and adjusted the seas and balance on a planetary model.






