Ip sog-ui geomeun ip (입 속의 검은 잎 The Black Leaf in My Mouth) is a poetry collection written by Ki Hyongdo. As Ki Hyongdo was preparing to publish the collection in 1989, he suddenly died from a stroke. The collection was published later that year. His early death added a sense of tragedy to the sorrow and despair that was already present in the first half of the collection and gave rise to the so-called “Ki Hyongdo Syndrome.”