<i>Daifuku-ji</i> rock-cliff sculpture is halfway up on a hill near a sea in Tateyama city, Chiba prefecture. It is sheltered by a wooden construction. The surface of the sculpture is covered with a thick crust which is composed mainly of gypsum due to the crystallization of soluble salts contained in the water in the rock. Much rain water penetrates into the rock of the hill where the sculpture is located and the water comes out from the surface of the rock. It is proved by chemical analysis that the water coming out from the rock contains a great amount of Ca²⁺ and SO₄^2-. Therefore, the best way to preserve the sculpture is to impede the migration of the water to the sculpture by some means. It is also quite effective to make the ambient humidity of the sculpture as high as possible so as to minimize the evaporation of water from the sculpture. Unless water is stopped from coming into the sculpture, any treatment applied directly to the sculpture, as for example impregnation with resin, should be considered dangerous because of exfoliation of the treated surface layer. -- AATA