Correct spelling is Miroku I believe. This is from CTD re Miroku:
MIROKU FIREARMS MFG. CO.
Current manufacturer established during 1893 and located in Kochi, Japan. Miroku currently manufactures long arms for Browning and Winchester (please refer to individual sections), in addition to their own line of firearms mostly distributed in Europe.
Shotguns marked Miroku only without another trademark listing represent that period of manufacture before Miroku began manufacturing shotguns for other companies (i.e. Charles Daly, Browning, and others). Most guns marked Miroku only were made on a limited basis and although somewhat rare, collector desirability to date has been minimal. Since model notations were not specified in most instances (many shotguns were made to test market demand), a model rundown is virtually impossible. Values can be approx. ascertained by comparing a Miroku shotgun of similar gauge, features, engraving/wood, and condition to an equivalent Japanese Charles Daly model.