If there's any place in Africa that might get more than passing notice from Japan, it's Ethiopia. And even then, it's less that Japan would want to colonize it, as much as they'd want to partner with the Solomonic Dynasty in modernizing the country. IOTL, there were even plans for a dynastic marriage between one of Haile Selassie's sons and a Japanese noblewoman, only for those plans to come crashing down with the Italian invasion. And even with the growing alignment between what would later become the Axis, it caused quite the diplomatic stink between Imperial Japan and Fascist Italy.