電波新聞社 (Radio Newspaper) of Japan was the parent company. They started a group to do software development and porting of games under the rather generic name マイコンソフト (Microcomputer Software). This got abbreviated somehow as YMCAT, which you can see mentioned on title screens and covers.
Later on they renamed themselves "Micomsoft", but still use the same logo. They also used the Dempa name with the same logo.
And they where also the Japanese reseller for VIFI International.