A crude paper, sadly, but if you can overlook the liberalism it makes for a decent summary and it makes some good points:

Korean [capitalist]s, as well as [Imperial] settlers in Korea, flocked to Manchuria after its annexation to take advantage of business opportunities. Koreans fought for Japan to escape their colonial status and earn imperial citizenship. Although Japan refused to extend the political and constitutional rights of its citizens to colonial subjects, the relationship between the [Imperial] and indigenous peoples lay on broader foundations than repression.

[…]

Because the Paris peace settlement sought to prevent the spread of Bolshevism as well as to contain Germany, the fear of the Soviet Union contributed significantly to the reluctance to stop Italy, Germany, and Japan. It also hastened the conclusion of the […] agreements in August 1939 that kept the Soviet Union neutral while allowing [Fascists] to attack Poland.

[…]

Stunned by the [1939] agreements, which allowed the Soviet Union to inflict a military defeat on the [Imperialists] in Manchuria, Japan later concluded a neutrality agreement with the Soviet Union, which left the [Fascists] to fight the Soviets on their own.

(Emphasis added.)