This volume traces the textual tradition and the reception in Japan of a short yet concise work known as the Twelve Gates Treatise 十二門論 (Chin. Shíèrménlùn; Jap. Jūnimonron; T 1568). The treatise is traditionally attributed to Nāgārjuna 龍樹 (c. 150–250 CE) and constitutes one of the eponymous ‘Three Treatises’ 三論 (Chin. sanlun, Jap. sanron) of the East-Asian development of Madhyamaka thought, known as Sanlun in Chinese and Sanron in Japanese. The treatise is devoted to the first aspect of the Eightfold Negation, the refutation of production (or arising) in order to illuminate the notion of emptiness 空 (Chin. kōng, Jap. kū). Even though the treatise and its most prominent commentary, the Shíèrménlùn Shū 十二門論疏 (T 1825) by the scholar-monk Jízàng 吉藏 (549–623), were transmitted to Japan already in the eighth century, the codified exegesis of this treatise began only in the eleventh century and reached its peak in the Kamakura period (1185–1333). On the basis of seven hitherto unstudied Japanese sub-commentaries, the present volume approaches this textual tradition in terms of its exegetical techniques, its literary style, and its doctrinal contents. The research is further substantiated by the study of the codicological and paleographic characteristics of the corresponding manuscripts and the reconstruction of the commentaries’ intertextual references as well as a biographical investigation into the authors of the texts, their genealogical relations, and their monastic networks. Through highlighting the commentarial literature, doctrinal debates 論議 (Jap. rongi), and the training of new monks this study sheds light on the revival of medieval Sanron studies and lays the foundation for future research on its subsequent historical development.