While one is historical and the other modern day, both dramas have a determined FL who is a single mother (either biological mother or aunt/adoptive mother) to a precocious little boy. The child takes a liking to the ML at the beginning and calls him his martial arts disciple. The ML has never met the little boy before but is related to him (father vs. uncle) and quickly steps into the role of father, all while falling in love with the FL.
Both are mini dramas with a poorer FL who is raising her little relative (nephew vs. little sister) alone, and a wealthy ML who moves in with the FL due to needing/wanting the child (to keep his business vs. fulfill his father's wishes). Both have a super cute supporting child actor who likes the ML right away, and both main couples have a somewhat antagonistic relationship at first that quickly warms to romance.