I recently watched the whole Nihon boryokudan series
. Here's my reviews from the other thread + a few additional screencaps for parts 1 & 3. I was too lazy to take caps for the rest.
Japan's Violent Gangs: Boss (aka Japan Organized Crime Boss) (日本暴力団 組長) (1969)
The first film in the transitional yakuza film series that paved way for the jitsuroku true account films of the 70s. Koji Tsuruta stars as an old school gangster boss who has become something of a fish out of water in the modern gangster world. Despite some ninkyo elements, and a soundtrack that resembles Teruo Ishii's contemporary gangster films, this movie already leans heavily towards the jitsuroku style. The opening disclaimer states the film to be fictional, but that's not entirely true as it was heavily influenced by true events (the Yamaguchi gang moving to the Kanto area). Director Kinji Fukasaku's trademarks are already in a steady use, including documentary like footage of violent chaos, effective use of still photos, and a nihilistic storyline. While the film is loaded with good performances - Noburu Ando being one of the many who deserve a mention - it's Tomisaburo Wakayama who is the real stand out as a drug addicted, volatile boss who is like a time bomb trying keep himself from exploding.
Oddly enough, Toei never released this film even on DVD.
Japan's Violent Gangs: The Boss and the Killers (日本暴力団 組長と刺客) (1969)
The 2nd film in the series that started with Kinji Fukasaku's Japan Organized Crime Boss. This follow up by director Junya Sato feels somewhat disappointing in contrast. The documentary-like touches and the energetic visual output that made its predecessor feel ahead of its time are mostly missing here, although the film does have a fittingly dark ending. Koji Tsuruta stars again, this time playing a gangster boss who assassinates a yakuza in broad daylight, gets a bullet in his arm in the process, and then hides in a small shop. The main storyline (about what happened before) is then told in flashbacks. Lots of talk ensues. Not terribly bad, just not that exciting either.
Japan's Violent Gangs: Degenerate Boss (日本暴力団 組長くずれ) (1970)
Koji Tsurura is a former yakuza gone straight, now running a jazzy night club, in the third film in the series. The films were not connected other than being part of the same series and all starring Tsuruta. This one was directed by Shin Takakuwa, whose brief filmography features one stand out (the superb Sonny Chiba cop drama A Narcotics Agent's Ballad, 1972) and handful of mediocre yakuza films. This film is sort of well made, with some steady handed cinematography, elegant use of colour and light (especially in the night club scenes) and a typically charismatic and stoic Tsuruta performance. However, it feels quite conventional compared to Fukasaku's film that was already reaching toward the 70s jitsuroku cinema. This one is a talkative film with the usual 'ex-yakuza trying to lead honest life while surrounded by underworld acquaintances' storyline. Not bad, and features a surprisingly sleazy op credits scene with a stripper, but a little pedestrian overall.
Japan's Violent Gangs: Loyalty Offering Murder (日本暴力団 殺しの盃) (1972)
The 4th and last in the series was helmed by Yasuo Furuhata, a director whose films I have never especially cared for. He made talkative, character driven crime dramas that were usually neither ninkyo nor jitsuroku films. I suppose there is more-than-usual character depth to be found in his films - if you find them interesting to begin with. It sometimes seemed like he shouldn't have been working in yakuza films in the first place, but in the drama genre where he later ended up. Anyway, Tsuruta is the lead again, this time a guest at a gambling house where he kills two attackers and has to flee from the city. He settles down with old friend and gangster boss Tetsuro Tamba, whose clan is in a conflict with another gang. Tsuruta starts helping him but angers Tamba's neurotic underling Rinichi Yamamoto in the process. Chris D declared this as one of his favourite yakuza films (out of the 1000 or so that he has seen). As often is the case, I don't quite understand where his opinion is rooted. There are some good scenes with Tsuruta and Tamba, and Yamamoto is good in his role, but none of it feels especially captivating. It's not a movie you'd call "bad", just one you don't care much for.