testing one's children by putting them through hardship
Proverbial expression derived from the belief that a lion pushes its cubs off a cliff to raise only the strong ones. Used metaphorically for strict parenting or tough love.
His educational policy is exactly like 'throwing the cubs off the cliff'—a tough-love approach.
As the saying 'shishi no ko otoshi' suggests, it is sometimes necessary to deliberately place children in harsh environments.
From the traditional belief that lions push their cubs off cliffs to test and strengthen them. The exact origin of this belief is uncertain, but it has become a fixed Japanese idiom.