Japan, differing from the Ottoman Empire, could not establish a unified state until the end of the 16th century and remained in a more vulnerable structure compared to its neighboring states in particular and external threats in general. In this context, the European states' reaching the borders of Japan and Japan's becoming a unified state within this framework covers the same period. As in the Ottoman Empire, military and political developments in Japan as well as the reforms and modernizations in the military fields as a result of these show a connection with the external factors that constitute the main threat. In the 18th century, due to different reasons, both the Ottoman Empire and Japan needed military reforms and the innovation processes in which Europe was based gained speed. When the military modernization attempts in the 19th century are examined, it can be mentioned that both states remained in the sphere of influence. In this context, relations with European states have been the most decisive issue for both states. Therefore, this situation made it possible to compare the renewal efforts of the two great states in their military fields over the following years. Thus, the modernization attempts of the Ottoman Empire and Japan in the military fields and the military modernization processes were examined in the Ottoman and Japanese context. It has been possible to create an integrative picture through the military measures taken and the reforms carried out by both states, which differ geographically, historically and culturally.