顾炎武的《日知录》是清代考据学的经典之作,其中卷五考证《仪礼·丧服》的内容中有“为所后者之祖、父母、妻,妻之父母、昆弟、昆弟之子若子”和“报于所为后之兄弟之子若子”两条,通过文献的梳理和分析可知,顾氏对这两条内容中“若子”的解释存在失误,应加辨正。 Gu Yanwu’s “Daily Record” is a classic of the Qing Dynasty textual criticism, of which the volume five textual research “Ritual mourning clothes” in the content of “the latter’s ancestor, parents, wives and wives parents, Kun The son of Ruo Kun ”and the“ son of Ruofu ”after“ the son of Ruo Youbu ”, we can see from the review and analysis of the literature that Gu’s interpretation of“ Ruo Zi ”in these two contents is wrong, Should be plus or minus.