Some related questions: Was it more common for Japanese men to marry Korean women, or vice-versa? What nationality would their children have been considered? What happened to these couples after 1945?
https://i.imgur.com/ZEYXMWH.png
For most of the colonial period, gender ratios were roughly even, though somewhat favoring Japanese husbands and Korean wives.
https://i.imgur.com/dhzShY4.png
The war period coincided with an astronomic increase in Korean husband and Japanese wife marriages.
There's a misunderstanding here though. While Korea was "Chosun," it was an annexed portion of the Empire of Japan and considered integral. Koreans were Japanese subjects, and there was an odd tendency within Japan regarding legal treatment toward them. In the home islands of Japan, Koreans had the full rights of Japanese citizens and could vote, run for political office, etc. In "Chosun," the colonial policy operated differently as native Koreans on Korean soil were seen as potential threats (separatism). Koreans in foreign lands (Manchuokuo/SEA) also came under the protection of the Japanese consulate, typically benefiting from imperialism away from Korea while being oppressed in their native lands. Koreans in the United States actually had to protest when the Japanese government tried to intervene in an international incident of white laborers attacking korean workers. The korean americans rejected status as Japanese nationals, insisting on their own national identity.
So, in the Empire of Japan, children of all ethnic Japanese and ethnic Koreans were treated as Japanese subjects/nationals/citizens. However, postwar resolutions stripped Japanese nationality from Korean-Japanese with no Japanese father. Some zainichi trace their roots to these people, and some couples repatriated to the North during extensive campaigns by the Japanese and North Korean government. (Once upon a time Japan was on friendlier terms with the North than the South)
This paper will interest you. Charts come directly from it. What I find interesting is that a socio-economically disadvantaged minority tended to have roughly equal to far greater KMJW relationships to JMKW ones.
