Africa was kind of all over. WWII left it in a mess with some parts of the continent being used by the allies for military bases and etc.
There are numerous mountains in Japan and they were an obstacle towards unifying the country. Since many parts of Japan waged wars against others, it was difficult to fight in other people's regions since they had the mountains to their advantage so there was a difficulty in uniting every part of Japan through wars, like it was done in numerous other countries.
Its own atomic bomb
hope this helps
Mochila would be your answer.
