This study delves into the finer details of the small regular-script version of the stele rubbings of Record of the Altar of the Immortal of Mount Magu (Magu xiantan ji), originally composed and written by the Tang statesman and calligrapher Yan Zhenqing (709-785). By clarifying the classifications and production background of various versions of rubbings of the original stele, the study provides an in-depth discussion on the calligraphic canonization process of this small regular-script version. Rubbings of the original stele made in small regular-script first became widely circulated and gained popularity during the Northen Song period, soon capturing attention and sparking discussions among the literati of that time. Created with the initial intention of preserving the original text, this emulated copy in small regular-script, with its unique calligraphic characteristics, inspired the creativity and imagination of many calligraphers. From the Northern Song to the late Qing, the recognition of the small regular-script version evolved: from a miniature replica with a questionable origin to a valued classic representation of Yan’s small regular-script calligraphy, imbued with dynamic aesthetic connotations over the centuries. However, with the reemergence of its progenitor rubbings in large regular-script and the advancement of image-copying technology applied in the publication of stele rubbings, the small regular-script version soon lost its critical acclaim and descended into obscurity, considered by many as a low-quality replica. This paper highlights the importance of the de-canonization of the small regular-script version of the stele rubbings of Record of the Altar of the Immortal of Mount Magu, offering an excellent example for researchers to discuss the reasons behind the canonization of calligraphy works. It also reveals the impact of alterations in replicas on later calligraphy learners’ understanding of the original work.