They could get to know each other without supervision.
and
They had a cheap fast mode of transportation to go to places and to get to school, home and work without the expense of a car.
The technology, logistics, and communication of the north that allowed them to defeat the south is because of their skill of having to manufacture supplies and weapons that they need for the war. They were able to create more weapons and be able to hire more soldiers.
Hope this helped :)
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Japan was in dire need of resources which lead them to further colonization of surrounding islands.
