1.
tough love; trial-by-fire upbringing
A child-rearing approach of deliberately exposing a child to hardship to make them stronger. The image comes from the legend that a lion pushes its cub off a cliff and raises only the one that climbs back up.
Comes from the saying 獅子は我が子を千尋の谷に落とす — "the lion drops its cub into a deep valley." Usually appears in the longer form 獅子の子落とし; the short form 子落とし is less common.
Usage
Describes a deliberately strict or harsh choice made out of belief that hardship strengthens the child. Carries a serious, sometimes admiring tone — not a casual term for ordinary discipline.