Mujie 墓碣 were grave tablets erected at the tomb of low- and mid-ranking officials. Persons who had occupied an office of rank 6 or 7 were entitled a memorial stele (mubei 墓碑) at their tomb. Persons without an official function were only entitled to be commemorated by simple tomb inscriptions (mubiao 墓表). The distinction in rank was been introduced during the Tang period 唐 (618-907), while the two expressions had been interchangeable in antiquity.
Another difference between mubei and mujie was the shape. While the high-ranking memorial stele (mubei) had square corners, the lower memorial tablets (mujie) had a round top, and could thus be compared to mountain tops (jie 嵑).
The inscriptions of all types of commemorative stones praised the virtues and achievements of tomb owners, and were often composed by famous writers. For this reason, many inscriptions are preserved, even if the object are no longer extant. Famous inscriptions (mujie wen 墓碣文, mujie ming 墓碣銘) of mujie grave tablets are Pan Ni's 潘尼 (c. 250-c. 311) Pan Huangmen jie 潘黃門碣 or Chen Zi'ang's 陳子昂 (661-702) Zhaoyizi Zhao shi jie song bing xu 昭夷子趙氏碣頌并序. From the latter example it can be seen that grave tablets had a laudatory purpose (song 頌) and might include an introduction (xu 序) before going over to the literary part.
Whether an epitaph is a mujie or a mubei can often only be said from the title of the inscription, but even then, the designation might be technically doubtful.
Rubbing of a large jie stele with a long inscription from the Jin period 金 (1115-1234). The inscription is incised on a pointed stone stele, bears a title in a variant of chancery script and a text in standard kaishu script. It consists of a long prose text, and a final eulogy (ming 銘) in poetical shape. From Wang 2014.