Actor Son Seok Koo revealed the secret to the "kiss scene".
On July 13th, on YouTube channel "China is a Class". A video of the title "[차이나는 밤샘토크] ‘키스신 장인’ 손석구씨, 창희 역할 탐났었다?! <나의 해방일지> 명장면 코멘터리 | 손석구 ep.3" was posted.
Son Seok Koo discussed the recently concluded JTBC drama "My Liberation Notes" with JTBC director Shin Ye Ri in the video.
Director Shin stated, "Since (the drama) is set in nature, there is only one kiss scene in the entire production, and it takes place in the middle of a mountain."
Son Seok Koo said, "After the kiss scene came out, a lot of comments said, 'What is this? What is this?' However, from the director's point of view, he did as much as he could, and in the script. Originally, we didn't even touch our lips, it was just like that. The director did his best though", he said, revealing the behind-the-scenes story.
In response, Director Shin said, "Nevertheless, after the scene came out, the fans gave him the nickname 'New Kissing Master'".
Seok Koo said, "I… I…Well", he paused "Not bad, the kissing scene", adding, "I don't like it, but I think I can do it well".
"It's also about being honest", he said when asked about the secret. "There are numerous kissing scenes that are obviously staged. I never do that. Because I prefer things that are more authentic. I'm not very good at being honest, but I do my best. I genuinely think it is real. I believe it is equivalent to action (acting). Even the kiss scene contains a line that makes me feel as though I'm not really experiencing it".
Source[1]