Gotta be less than 10 years, but Bum's always looked younger and more frail though. I always thought it was a 4 year gap, and now it looks closer to 7.
I remember in one of the first few chapters that Sangwoo said Bum was middle aged. That was literally the only clue.
LOL ε=ε=(ノ≧∇≦)ノ
He was probably just being mean. Bum joined college 4 years late, so he is most likely 4-6 years older than sangwoo.
It's not the only clue.
http://www.mangago.zone/read-manga/killing_stalking/mf/m_chapter-41/pg-39/
I don't take this special as canon to be honest, but accordingly to their appearance and the fact that it is set on Christmas, Sangwoo is 11 months old (since he is born on 27th of January) so Bum is 4 years old.
Middle aged was a mistranslation though
Hmm I was kinda thinking based on the way the millitary service works here that they would have at least 2 years age gap but I guess I was wrong
Don't worry... They make us think one thing, then turn around say BAM! YOU'RE WRONG!! #－.－)
Might not be a mistranslation. Remember a lot of these stories (manhwa/manhua & manga), have characters that call people like 28yrs+, old....man or woman.
╮(￣▽￣)╭ ....though you COULD be right.
I hate to be that person but.....boiiii I had like no clue about that age gap!