Though the history of the use of mortars in warfare can be traced back centuries, it was in the period of Japanese rule when the standardized and systemized uses of mortars in the battlefield were reintroduced by the Imperial Japanese Army; the new applications of the old mortars were reinvented. Especially in mountain warfare, the mortars were used in the garrison of the lines of the frontier guards in the mountain passes, fire support for the attacks, capturing of dominant positions, defense for the gun emplacements, expanding defense depth, and baulking the aboriginals' expert counterattack. Therefore, the reintroduction and reinventing uses of the mortars played key roles in the success of the execution of the plan for the management of the aboriginals during the period of Japanese rule.