This thesis includes an analysis of Japanese history at the turn of the 19th to the 20th century, focusing on the Meiji period and all the changes that occurred during that period. The work is divided into chapters that describe the history of the shogunate, especially the Tokugawa shogunate, and chapters that describe in detail the Meiji period and all the reforms that took place in the economy, the army, education and society. It also describes the very expansionism of the Japanese Empire at that time. After the introductory first chapter, the second chapter describes the shogunate, and as already stated in the previous paragraph, it describes the Tokugawa shogunate in more detail. It talks about the rule of the shogunate, when the shogunate was created, and what their government consists of. The paper describes the Tokugawa shogunate in more detail and describes the course of their rule and the events that led to the fall of the Tokugawa shogunate, which eventually led to the Meiji period, that is, to the return of the emperor. The third chapter describes the rule of an emperor who had almost no powers during the shogunate period, and this chapter describes the change in the emperor's powers when the Meiji period began. The fourth chapter describes the political changes and talks about the institutions that were created, but also about the laws and the constitution that were passed. The fifth chapter describes the military development and talks about the three transition phases that took place in order for the army to transition into a modern military organization. In the sixth chapter, economic development is discussed in detail, the changes that have taken place in finance and infrastructure, and it is also described which are the key products that they "took" from foreign experts in order to modernize their economy. This chapter also discusses the emergence of the zaibatsu, which are also called the "financial clique". The seventh chapter describes the development of education and the new system of compulsory education introduced. The eighth chapter describes the development of society. It describes the classes that make up Japanese society. The ninth chapter, and the last chapter of this paper, focuses on Japanese expansionism. The Sino-Japanese war, the Russian-Japanese war and the annexation of Korea are described. Their course, main battles and finally their ending are described in detail.