Since the Meiji Restoration, the construction of the fortifications of traditional redoubts was an essential skill of infantry training; there were various kinds of standardizations for the constructions of the redoubt fortifications in the basic military textbooks. When the rule of Imperial Japan began in the mountainous areas in Taiwan in the 1900s, the construction of redoubt fortifications improved with the progress of the weapons used by the indigenous peoples; from the use of spears and guns and the exchange of attack and defense relationships, both sides learned strategies from the other. The construction of the redoubts might have been the least significant part of the fortifications for the frontier guards in the mountain passes, even not listed on the map legends, but, in the real combats, the transformations of the redoubts symbolized the dialectical relationship between the attack and the defense. Furthermore, they also detailed the labor conditions and the crucial battle infrastructures in the lines of the frontier guards in the mountain passes.