Screenwriter Yasushi Fukuda got the idea for the series after interviewing a former prosecutor turned lawyer, who told him that 99.9% of a prosecutor's job is deskwork; Fukuda then imagined what would happen if a prosecutor actually went out to investigate cases himself and left his desk full of pending files.

After the original 2001 series ended, production received a flood of remake rights requests from South Korea, Taiwan, Hong Kong and Singapore, but producers refused every time, insisting the lead prosecutor role could only ever be played by Takuya Kimura.

Takuya Kimura himself reportedly avoided doing a sequel to his own hit series for years, which is part of why a continuation did not happen until the 2006 special, five years after the original run.

The original 2001 series averaged a 34.3% audience rating and peaked at 36.8% in the Kanto region, making it the biggest hit of the Getsuku (Monday 9pm) timeslot in the mid-Heisei era, with every single episode scoring over 30%.

J-pop star Hikaru Utada, who sang the theme song 'Can You Keep A Secret?', made her onscreen acting debut with a cameo as a waitress in episode 8; she appeared for only about 14 seconds, and that episode drew the series' peak rating of 36.8%.

For the 2006 special, the crew filmed a train departure scene using two national-JR-liveried Kiha 58/65 diesel railcars that were, by that time, no longer running in Yamaguchi Prefecture at all but were borrowed from JR Shikoku, where they still operated in that classic livery; Kimura's character rode in the Kiha 65 car.

The 'agoma' delicacy (a smoked, pungent liver preserve of ishigaki-dai fish) featured in the 2006 special, as well as the fictional Yamaguchi town of Nijigaura itself, were entirely invented for the drama and do not exist in reality.

Two products referenced in episode 1 of the original series, the Nagano specialty 'Zukuzuku' and the local sake 'Kumagorosi,' were fictional items created specifically for the show and do not actually exist.

A fictitious research institute called the 'Bridge Engineering Research Institute,' visited by Kuryu in season 2 episode 5, does not really exist; the scene was actually filmed at the real Ship Research Institute in Mitaka, Tokyo.

For the 2015 Universal Studios Japan tie-in event promoting the second film, the show's bar set was recreated complete with a hyper-realistic animatronic figure of the bartender, built using Universal's 'Chronoid' technology, that closely resembled actor Yoji Tanaka himself.

Actor Kiyoshi Kodama, who played prosecutor Toshimitsu Nabeshima in the first series, died in May 2011; the second season's first episode credited him with a 'Special Thanks' in the end credits in tribute.