The actress who plays the woman who is killed at the start of the film reappears in a completely different role - an enemy operative - in the second half of the film.
Sets used for this film/double episode were later reused for The Prisoner (1967). Many actors from the series appear in this film. This film edits together the first two episodes of what was to have been the third season of Secret Agent (1964). After filming these episodes, Patrick McGoohan quit the series in order to create The Prisoner (1967) The character of Potter, played by 'Christopher Benjamin', reappears in an episodes of The Prisoner (1967), which is considered evidence of the lead character of the series (referred to only as No. 6) was in fact John Drake.
Koroshi means "murder scene" in Japanese.
Filmed in 1966 but not broadcast in America until 1969.