The series is based on the novel The Dark Manual by Colin O'Sullivan.
Masa's distinctive workplace (actually the Kyoto International Conference Center) was also featured in the finale of The Challenge (1982) (1982), starring Scott Glenn and Toshirô Mifune.
Masa's mother, Noriko, is played by a Taiwanese singer and actress who attended university in Japan and later became a naturalized citizen. Her grandfather was a key figure in early 20th-century Chinese history, participating in the Chinese Revolutionary Alliance and resisting Japanese forces during the Sino-Japanese War. In her own words, she likens Taiwan to her "natural mother" and Japan to her "foster mother," reflecting a nuanced cultural identity that resonates throughout her artistic (Japanese woodblock-prints) and personal endeavors.