There's a brief history of Christianity in Korea at this link.
Who Brought the Gospel to Korea? Koreans Did.
I don't know of any Korean Christians. Koreans are thin on the ground in Australia anyway, although the last time I went to an optometrist, he was Korean. We had a brief discussion about volleyball played with their feet. I'd seen it in action at a nearby park.
It turned out the people playing it were Khmers. They're pretty good at it too.
The optometrist said it was also very strong in Korea. Every young Korean has to do military service if they can, and they use that game as part of their physical fitness training.
In the above article, there is a line viz. -
The famous revival in 1907 occurred at a time of crisis as the nation was being lost.
This reminds me of a quote about major revivals in a Lion Book, which I've struggled to find again (the quote). But it was along the lines that major revivals usually occur at one of three times -
1. National renewal eg. Wesleyan revivals.
2. A time of crisis (which fits the above - the Welsh Revival took place in 1912, 2 years before WWI).
3. The end of a civilization (eg. Roman Empire, Medieval Europe and so on).
So if we're praying for a major revival, we need to keep that in mind.