What was nicholas ii's main reason for going to war with japan?
a. to pay for the massive costs of russia's grain exports
b. to expand russia's territory by taking parts of china
c. to keep his people from rebelling against his government
d. to earn a great victory that would make him popular.

 Nicholas II's main reason for going to war with Japan was: C. to keep his people from rebelling against his government

By going to war with Japan, Nicholas created a common enemy for all the people in his rules and diverting their attention for any potential thought to create a rebellion against his government.