As the first piece of Hangul literature, the Korean Bible proved to be a thorn in the side of imperial Japan. It sparked a "Hangul movement," leading to the publication of newspapers, poems, and novels in the indigenous tongue. Throughout Japanese occupation, the Koreans’ desire for independence became closely linked with their desire to use their own language. As one student of Korean nationalism, Vernon Blake Killingsworth, has written, "The Bible did more than just sustain hope; for Christians and non-Christians alike, the Hangul Scriptures served as a symbol of Korean culture."
The independence nurtured by Korea’s indigenous church stood directly opposed to Japan’s imperial policies. Indeed, many congregations took risks to promote Korean freedom. Unlike other countries, where missionary congregations sometimes found themselves entangled with colonial powers, Korea’s church was always allied with Korean nationalism—an alliance that proved beneficial for both church and state.
How Christianity Liberated South Korea
Christian missions is not about replacing indigenous cultures with western or any other culture. It is about inserting truth into culture and tearing down falsehoods, and liberating people. The case of Korea is nicely outlined in this article from CT. Here’s a couple quotes: