Answer:
Isolation and geography, rapid modernization, being a colonizer itself, and War.
Step-by-step explanation:
Isolation and geography - Japan was a remote, mountainous island which will be a hassle for Europeans to conquer especially over 120 years ago. Also Japanese governments during this time placed strict laws that limited outside influence.
Rapid modernization - They become to create more democratic and free laws that allowed Japanese citizens to display their full potential, instead of being just farmers.
Being a colonizer - Japan was a colonizer itself colonizing the Korean Peninsula from 1910 - 1945, which is why the two cultures share so much in common. This colonization allowed Japan to keep itself more distant from colonial rule and allowed it to assert dominance over the East Asian area.
War - Japan, when many Europeans first arrived, was in a middle of a war within itself. A period of warring states caused division throughout the islands which may have drawn Europeans away.
Theirs probably more I'm missing, but hopes this helps!