**Acknowledgments**

This study was supported by JSPS KAKENHI Grant Number 20520047 and 17K02216 (Japan Society for the Promotion of Science) and INDAS-South Asia (Integrated Area Studies on South Asia, National Institute for the Humanities). This publication was financed by Kibankeihi funding (2016–2021 fiscal years, Hiroshima University). I would like to express my heartfelt thanks to the two peer-reviewers for carefully checking my manuscript, and their thought-provoking comments. I also appreciate many scholars, particularly Dr. Kimiaki Tanaka, for having provided his picture of the Heruka man. d. ala (Figure 1), and Dr. David Gray, Dr. Makoto Kitada, Dr. Olga Serbaeva, Dr. Iain Sinclair, Dr. Ryugen Tanemura, and Dr. Toru Tomabechi (alphabetical order), for helpful advice and suggestions. I am responsible for any mistake that may be found in this monograph. Finally, I pay my highest respect to Mr. Takashi Maeda, who conducted pioneering research into the *D. ak¯ ar¯ n. ava* 15, and I give special thanks to my dear wife.
