Both of them are navy uniforms of imperial Japan, which were also used during WW2, where the start of Hetalia takes place.
Additionally, the fan that "Left Japan" is holding has the Rising Sun Flag on it. Since the late 19th century, this flag was used as the war flag of imperial Japan until the end of WW2 (1945).
In present day, the flag is used as the war flag and naval ensign of the Japanese self-defense force.
posted over a year ago
Thanks a lot for the answer. I Have become interested in this time of japan after seeing the Scene where Seita is taken to see an officer after he steals food in Studio ghiibli's "Grave of the fireflies"