Culture: Only 15% of the land is good enough for farming, they had plenty of rain which helped the rice and other crops grow. Japan is located right next to the ocean so they have a lot of fish.
Another benefit from the ocean was the ocean helped protect from foreign invasions. Some dangerous landforms are: earthquakes, volcanoes and tidal waves. Japanese islands had very few natural fuels like coal and oil.
Sources: https://en.m.wikipedia.org/wiki/Flag_of_South_Korea Https://www.google.com/search?q=chinese+flag&safe=strict&client=safari&hl=en&prmd=isnv&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiPiMecuMzRAhWnsFQKHZw6DswQ_AUIBygB&biw=1024&bih=672#imgdii=1Q4kSysFFNfPlM%3A%3B1Q4kSysFFNfPlM%3A%3BhtyLxRDiN0YrvM%3A &imgrc=1Q4kSysFFNfPlM%3Ahttp://culturalhealthsolutions.com/serving-up-some-rice-advice/