Why are 64 cultural relics forbidden to go out for exhibition?

In order to ensure the safety of cultural relics exhibited abroad, fragile cultural relics, orphans in first-class cultural relics and paintings before Yuan Dynasty (including Yuan Dynasty) are not allowed to be exhibited abroad. The following cultural relics are forbidden to be exhibited abroad: 1. Ancient bodies unearthed in past dynasties; 2. The main statue of a religious site; 3. The texture is ivory and rhinoceros horn; 4. Painting, calligraphy and silk reeling works before Yuan Dynasty; 5. Representative solitary porcelain in Song and Yuan Dynasties. The following cultural relics are cultural relics 1, and bamboo slips and silk books restricted from going abroad for exhibition: 2. Ancient books written in the Tang Dynasty and engraved in the Song Dynasty; 3. Large-scale complete silk fabrics before the Song Dynasty; 4. Large murals and important murals; 5. Mausoleum stone carving.