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 À armes égales (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.