As I studied in Korea for some time, I have also experienced the subtle and not so subtle differences in how Christianity is practiced. I want to organize my findings here. I may or may not follow this up with a more historical look on how Korea came to be the one East Asian country with a significant Christian population, but this will just be my experiences on how Koreans practice their faith, how Christian communities are organized, and what standing religion has in Korean society.
Of course, everything here is based on experience and opinion. I by no means claim these to be universal truths. These are “Essays” and not “Theses” on Asia after all. So, please continue with caution.

Let me preface this with some information on me. I am from Germany, a historically Christian-influenced country, also the birthplace of Martin Luther. I grew up in the East (the “New Federal States” that were established after the German Reunification 1989/90). The East was socialist, and the socialist government tried to get rid of religious influence as much as possible. Even though that didn’t fully work, there are more Non-Christians in the East than the West. In Germany, Protestants and Catholics both make up about 25% of the population, but the area I grew up in is predominantly protestant, specifically “Evangelical-Lutheran”. Christians in Germany are often very “lax”, or “liberal” on their belief, most people identifying as Christian might not even attend church regularly. It is a thing you are usually born into, and experiences like “being born again”, like American Evangelicals often talk about, is not usually a thing. Thus, the amount of Christians in Germany is steadily declining.
The last thing I want to mention in preface is that Religion is something wholly private in Germany. Like politics, you don’t usually talk about it much. Missionaries and such things are hugely frowned upon. Germany is secular, although not perfectly. The government does collect the church tax for the church, the preamble of the Constitution does talk about God, and mist chancellors in German history have been from the CDU, “Christian Democratic Union”, although the “Christan” basically just refers to a vague and inclusionary Christian-Social idealism, I guess.
That is the angle I am looking from. In Korea, I have attended a Presbyterian Church. Presbyterianism is a weird, fringe offshoot of Protestantism that swept over from Scottland with the first Christian missionaries in Korea. It is the by far most prevalent denomination in South Korea. I have attended this church regularly, but also looked into others. I have not, however, gathered any experience with Catholic communities. Catholics are less numerous than Protestants (about 29% of Koreans are Christians, made up of 18% Protestants and 11% Catholics).
In this regard, with my background and limitations stated, I came to find that there are three big, relevant differences in “German” and “Korean” Christianity: Strict (Patriarchal) Structures, Politics, and Social Conservatism.
1. Christianity in South Korea is stricter/more rigid.
With this, I mean that the community is more rigid, it is structured and attendees are more devoted. The belief in itself seems to demand more from the believers. Christians (the ones I met anyway) pray before meals, some attend church several times a week, they have bible reading groups and post-service recollection gatherings where they talk about what they learned and how to apply the teachings in their life. They are well organized, in a rigidly structured way. Typical for Koreans, the services are segregated by age: Child services, youth services, “normal” services for older members. I attended the youth services (청년부, cheongnyeonbu), which apparently reach from the end of high school to usually when you marry, but that can vary from case to case. On special occasions, all members attend the same service (대예배, daeyebae), this happens e.g. on Christmas or New Years.
In Germany, most people go into church and leave afterwards. The church is not a big part of your social circle, usually. That seems to be different in Korea: The team leaders of your group are hellbound on getting you to go out with your group, let it be for dinner or a field trip. Of course, your bible will be something you need in all of these.
I was a bit struggling how to put this point into words, which is why the title might not be the best. You could maybe say the community is “tighter”, more demanding, or any variation of that.
2. Christianity in South Korea is political.
Korea is a secular country. There shouldn’t be much direct political influence the church (or some churches) can flex. However, it is sadly not that simple:
Former South Korean President and Mayor of Seoul Lee Myung-bak (이명박) has been convicted of bribery, embezzlement and tax evasion and, since 2018, serves a 17 year prison sentence. Now, criminal presidents are nothing new in Korea, but Lee is quite an interesting case. What is relevant for us here is that he attended Somang Presbytarian Church, where he is still listed as an “elder” (장로, jang-ro). He seems devout and he seems to like his church. However, he apparently likes his church so much that he gave several high ranking official posts to members of his community. That is fishy, to say the least, and portraits a bigger problem within Korean Churches: Members of church communities depend on each other to guide them to positions, thus networking their way into high ranking jobs using these “closed societies”. Certainly, this sort of networking is normal in Korea (Parasite portrayed it nicely), but when church communities are birthplaces for political high society, it does beg the question: How secular is South Korea, really?

With prominent and influential church members being high profile political figures, using their networks to gain favours and power, churches inevitably get drawn onto the stage of the political theatre. This sort of direct influence on the political landscape is highly questionable, and but one symptom of the problems South Korea’s political culture has to deal with.
3. Christians in South Korea are incredibly socially conservative.
I imagine that this is the least suprising thing for most people. “Wow, religios people tend to be conservative, what a revelation.” you might say. It is certainly no surprise that Christians in Korea will not support gay marriage or the right to choose. But still, the extend to how strong these beliefs are is astounding, but that is ultimately a result of where I come from: In Germany, Christians (with this I mean Protestants, remember) are far more liberal. That even young (Christian) women (women are on average much more left-leaning than men in South Korea, and probably all over the world, but I don’t know actual numbers for the latter) oppose such ideas this strictly is in my view a significant difference. Sure, elder Christians in Germany might oppose gay marriage, but I have literally not met a single person in my age group or lower, Christian or not, that has any problems with it, and although they probably do exist somewhere, they are very, very insignificant. On the other hand, the division between Christian-held beliefs and “Atheist-held” beliefs is more stark in Korea. As Christians in Korea seem more likely to want to “spread” their ideals than in Germany (as I mentioned: Religion is something private in Germany, whereas in Korea, missionaries going to other countries are still very much a thing, and many people I spoke to have expressed their belief that they should try to reach out to others about their religion as well), they are also not simply private opinions, they are a foundation of set beliefs that members and churches might try to spread. This goes a long way: Many Christians I met have expressed that they most probably couldn’t marry a Non-Christian, e.g.
These have been points that I think differentiate Christianity in Germany from Christianity in South Korea. Thank you for reading.