What would have to be done so that Japan and Korea are of near equal power, or at least the conquest of one or the other would be too difficult to be practical for the invader?
In many timelines I have seen it seems that Japan almost always takes over Korea. I find that is not necessarily the case, it was only comparatively recently that Japan managed to gain a dominant edge over Korea. What if, instead of Japanese dominion, the Koreans gather enough strength to be able to prevent the Japanese, or its neighbours for that matter, from taking it over.
Obviously China and Russia will be big problems. China could fall into a similar disarray as it fell into OTL at the turn of the century and Russia might not necessarily make it as far as the Pacific. The Japanese also opened themselves to the West, in any meaningful sense I mean, earlier than the Koreans, so perhaps a Korean Meiji Restoration occuring at a similar time, not impossible, could save the peninsula.
On thing of interest might be the Japanese and Koreans looking for aid from outside sources. For the sake of an example let us say that the Japanese sign a treaty with the British, providing military assistance and arms trade. The Koreans might respond by singing a similar treaty with the French or Spanish. How might this international dynamic affect the development of the Far East?
What do you think?