Items which were not collected because of bias include such things as pre-Song pottery, for this largely consisted of burial objects: who would dare to present such things to the emperor when wishing him long life on his birthday?
有偏見不收藏的，如宋以前的陶器多是陪葬的明器，那有人敢在皇上萬歲時獻上去「祝壽」？墓碑拓本，也是宮廷少收的「不祥之物」。