"Army of Shadows") is a Japanese television jidaigeki show featuring Sonny Chiba that ran for four seasons in the early 1980s.
The first season was a reimagining of the 1980 film Kage no Gundan: Hattori Hanzō directed by Eiichi Kudo.
Quentin Tarantino stated in the supplementary material on the Kill Bill DVD that the character was named in tribute to Chiba's former role as Hattori Hanzō (the historical 16th-century Iga ninja) in Shadow Warriors (Kage no Gundan).
The implication is that the character in Kill Bill, whom Tarantino called Hattori Hanzō XIV, is another descendant of the same lineage.
A digitized version of a promo image for the series' second season infamously appears on the title screen of The Revenge of Shinobi.