[Oh, that was a subtle hit. It seems there might be some intentionality to it. Anyway, since it landed before the down, it probably won't be called a foul. The match has been briefly paused.]
[It's a bit ambiguous. According to World One rules, if even one of a fighter's knees touches the ground, they can't be attacked.]
[Here's the slow-motion replay.]
In slow motion, it appeared that Lee Il-su had launched a kick just as one of Ryusei's knees touched the ground.
[Ah, that kick landed when Ryusei's knee was down. It might not have been intentional, but it is a foul.]
[This can happen when fighters are in an excited state. The referee is giving Lee Il-su a warning. Oh, a doctor is coming to check Ryusei's ear. It seems the kick might have grazed his ear, causing a small tear.]
Blood was seeping from the tip of Ryusei's ear, but it wasn't a major bleed.
[Now we're seeing the replay of Lee Il-su hitting Ryusei's body.]