tl;dr: It seems clear that Japan eventually took control of - and annexed - Korea in 1910 in a way indistinguishable from colonies, but did Japan gradually go from (forced) trade with Korea to full-control of Korea as a series of ad hoc practical decisions or did it intend to "conquer" from the very start? Is there any real technicality in the word "conquer" to support the (revisionist?) claim they didn't conquer Korea?
From my limited AP US understanding of history, I had understood that Japan conquered Korea as part of imperialism and was motivated by resources, ideology, and racism.
However, in a posting of the famous humorous "History of Japan" video to nicovideo (you may have to turn on NG comments), there are various objections made (some rightfully so). One section in particular (5:21) had a lot of comments: While many comments effectively agree, many comments object that Korea was not "conquered" (征服). One comment said that Japan (my translation) "freed Korea from China and recognized The Korean Empire." Obviously that statement isn't true by the time WWII comes along, and I'm not sure it made sense at the time either tbh, but still - upon further cursory research - it did turn out to be way more complicated than just a simple takeover.
The year that the video points to as Japan "conquering" Korea is 1894 - when Japan and Qing China fight over influence of Korea in the first Sino-Jpn War. However, it also seems that this goes back even further to a series of many treaties starting with the "Japan–Korea Treaty of 1876" in which an unfair treaty was coerced (Japanese-favored trade, aid, extraterritoriality), all the way up to the one that finally annexed Korea in 1910 (not signed by Gojong). The one in 1876, while unfair, does declare Korea free as a sovereign state. Wikipedia even says that a Japanese published newspaper "advocated for constitutional government, freedom of speech, strong rule of law and legal rights, and Korean-led industrialization." Obviously there's a practical motive to all politics, but all this is to say I'm very confused, especially taking the Russo-Japanese war and growing Japanese disillusionment/shifting attitudes into consideration (apparently Greater East Asia Co-Prosperity Sphere wasn't a thing until after this?).
So yea. Are these commenters focusing on a technicality and obscuring a large part of the story? This is nicovideo after all - lots of netouyo (nippon netizen neo-nationalists). (To this point, one comment implicitly accuses them of historical revisionism.) Or, were they really treated (or intended to be treated) in a significantly different sense from other "conquered" states? How bad was it from 1905-1910 for Koreans, and why the shift in their treatment? Was the idea of an independent Korea taken seriously or just as propoganda? I know it's a lot of questions, but I realized I really didn't understand Japan's perception or motives about Korea's statehood around this time period.
Following a string of devastating military defeats in the 17th century, Korea had become a tributary state of the Manchu state, meaning that it recognized Qing's hegemony but enjoyed near-independence in its domestic affairs. By the latter half of the 19th Century, the Qing began to attempt to exert greater influence in Korea in a way that is more familiar to Western neoimperialism's colonial sphere of influences, which was met by heavy resistance on the part of the Koreans. Meanwhile, Japan, having just begun to Westernize through the Meiji restoration, began to look outward, formally annexing Ryukyu and debating whether to invade Korea (already in the 1870s!) as the first step to establishing its sphere of influence. By the 1890s, it was already an established policy goal of Japan to put Korea in its sphere, although much debating was on whether Korea should remain nominally independent or fully annexed as part of Japan. Japan's severing of Korea's tributary relationship with China through the 1st Sino-Japanese War was but one of the steps (which began with unequal treaties in early 1880s) in making it easier for Japanese interests to infiltrate Korea. By this point, Korea was stuck in a diplomatic hell where it had to play off Japan, China, and later Russia against each other to protect its precarious sovereignty, at times calling on relatively less invested powers (U.S., Germany) for intervention which never came. By Japan's victory in the Russo-Japanese War in 1905, Japan enjoyed uncontested influence over Korea, and many Koreans at the time rightly viewed this outcome as doom for their country. Indeed, Korea would lose its diplomatic sovereignty that year and be fully annexed as a Japanese colony mere five years later. On another note, Korea was not a belligerent in the 1st Sino-Japanese War although key battles took place in it. Korea at this point was spiraling into disaster with crushing debt, heavily political infighting, frequent peasant rebellions, and inability to enact meaningful reforms, which meant that it was unable to mount significant military resistance to foreign powers duking it out in their own land. In fact, it was Korea calling for help from China to put down a peasant rebellion and Japan also dispatching troops to Korea in response that triggered the Sino-Japanese War.