《左傳》記載鄭子家卒，鄭人為了追究子家弒君之罪，乃「斲子家之棺而逐其族」。過去學界大都在杜預的基礎上認為斲棺即斲薄其棺木，屬降格處置。但根據考古發掘的材料來看，古代棺制規格不僅限於棺板厚度，就連尺寸大小亦有所差異，因此僅用斲薄的方式不太可能作到真正的降格處置。筆者認為斲棺實際作法當指「剖棺見屍」。至於上博簡〈鄭子家喪〉的「利木三寸」是斲棺後的動作，並非等同於斲棺。即鄭人乃更換「栗木三寸」的小棺來羞辱子家，以降低其喪葬規格。「毋敢丁門而出」，是指鄭子家不得出西城正門而葬，意味著其不得葬入東城鄭國貴族兆域中。「掩之城基」，更直接將子家視為庶人看待，這些皆屬降格處置的作法。

According to Zuo Tradition, after the death of Zheng Zi-Jia, the people of Zheng “destroy Zi-Jia’s coffin and expel his clansmen” as a punishment for his crime of murdering the king. This paper aims to examine the symbols of degradation in funeral ceremony in the Spring and Autumn period, such as “destroying a coffin” and “limu sancun.” Influenced by Du Yu’s studies, scholars over the past few years have believed that “destroying a coffin,” means thinning a coffin. However, according to an archaeological excavation, thinning a coffin could hardly fulfill the intention of degradation, since the specification of an ancient coffin involves not only the thickness of wood but also the different sizes of coffins. The author suggests that the actual practice of destroying a coffin is “splitting a coffin and exposing the body.” As for “limu sancun” in “Death of Zheng Zi-Jia,” collected in the Shanghai Museum bamboo slips, it is not the act of coffin splitting itself, but the act done after the splitting of the coffin. To put it more clearly, the people of Zheng humiliate Zi-Jia and lower his funeral standard by placing his body in a small “3-inch chestnut coffin.” “Daring not exit from the Ding Gate” means that Zheng Zi-Jia is not allowed to be buried outside the Main Gate of West city, and no longer recognized as a nobility. “Being buried under the base of the city” also directly points out that Zi-Jia is regarded as a commoner. All of the above are practices to show degradation in the Spring and Autumn Period.