This is the fab box art of Crown's Ultra King 3 クラウンモデル SFカートシリーズ ウルトラキング３号. Is the spaceship at the back Project SWORD's Probe Force 1? What do you think readers?
Reader Paul Copeland has also kindly sent me the link to this Japanese You Tube Mandarake video about this old kit. He has also solved a personal mystery of his we posted on the blog a while ago but more on this later!