Yakusan's Lake

Yakusan asked a newly-arrived monk, "Where you come from?" The monk answered, "From the Southern Lake." "Is the late full or not?" inquired Yakusan. "Not yet," the monk replied. "There has been so much rain, why isn't the lake filled?" Yakusan asked. The monk remained silent.

When a new monk arrives at a monastery, the first question asked him is, usually, where have you come from, that is, from whom have you learned Zen? Here the lake is not only a geographical lake; it symbolises the monk himself, his mind, his understanding. The monk was really quite a simpleton in Zen as his answers reveal, Yakusan cornered him: "There has been so much rain, why isn't the lake filled?" We are showered everyday by the Dharma rain (truth). Why is the lake not filled?