Though there are other earlier accounts, the one I remembered most and have now found the detail, is the story about how foreigners carrying loads of bibles were killed and that the bibles were used as wallpapers in Korean homes, where the Bible was unwittingly introduced to visitors.
This is the account of Robert Jermain Thomas, born 1839, allegedly the first protestant martyr in Korea. Thomas married Caroline Godfrey, who shared mission field vision and went to Shanghai dispatched by London Missionary Society (LMS). Caroline unfortunately miscarried and passed away. Thomas wished to resign due to grief despite having even more zeal to completely serve and praise the Lord.
Then after being introduced by Alexander Williamson of the National Bible Society to Korean Catholics who had no Bibles, Thomas was greatly interested to serve in the "Hermit Kingdom" (Korea - fearful government of foreign influence and forbade contacts with westerners) where western literatures such as Bibles were banned and punishable with death for both distributors and recipients. Nonetheless, Thomas, helped by the Scottish Bible Society, obtained large number of Chinese Bibles for Korea, and found there were some willing to risk reading the Bible.
However, on a trip nearing Pyongyang, a group of hostile Koreans wrecked the Thomas' bible carrying American ship, Thomas was eventually killed, with some account that he begged them to take the Bible before being executed. The Bibles were then taken to the Korean homes but was ordered to be destroyed. All but one government official (Pak Yong-Sik) obeyed. Pak used the pages to wallpaper his house, which was later bought by Choi Chi Ryang, who knew of Thomas' event. 15 years after Thomas' death, Pyongyang was already holding around 100 churches and 1907 was a site of a major revival. Today there stood the Robert Jermain Thomas Memorial Church.