For Germany, the nation-state had its antecedents with Franco -Prussian war in the late 1800s and Japan in the Russia-Japanese war that lead to creating the modern nation-state. A clear example of similarities between this two models is found in that Japan set its constitution according to the German constitution. Furthermore: the public educational system in Japan also had many similarities with the German public educational system.
Nationalism was key for this purpose: it helped consolidate power for Germany and Japan as recently formed modern states, and as a result, both states became international actors posing changes and threats in the politic and economic relations of the region and eventually in the world.
Similarities:
In the case of Germany and Japan, it helped unite people with the common language and cultural background. It created a deep sense of belonging among them. Before the rise of this nation-states for the case of both, there was already a role in politics and regional- foreign trade but it wasn't until they consolidated at states that it became also a power over the region. (Germany as a fully emerged power in Europe and Japan in Asia).
Differences:
Japan had been in a isolation for a very long time under a whole different cultural system (the Shogun) and with the emergence of the nationalism under the rule of Emperor Meiji it started to fully engage in the foreign trade that also eventually paved the way for the creation of a powerful army. (Without Japanese nationalism it would have been hard to imagine the onward expansion and intervention abroad).
