A young Korean martial artist, Choi Bae-dal, is tricked by Japanese propaganda into applying to join the Japanese air force. Upon getting to Japan, he finds that, as a Korean, he will be treated as a prisoner and forced to fly a kamikaze mission - unless he can win his freedom in hand-to-hand combat against the Japanese General Kato. He loses, but to the Japanese soldiers' surprise, actually manages to make the general bleed.
In post-war Japan, Bae-dal finds work, but has violent clashes with the local Yakuza branch. He ends up becoming a rickshaw driver by day and a violent vigilante at night, defending Japanese women and Korean countrymen from American soldiers who harm the locals. Unfortunately, the Yakuza aren't willing to let the Koreans live peacefully, and they kill Bae-dal's mentor. After this, Bae-dal resolves to train himself to become the most invincible martial artist in Japan, and retreats to the mountains for a Training from Hell. The man who descends is a new Bae-dal, now calling himself Masutatsu Oyama, who starts entering every martial arts school he finds to defeat the maters and any student willing to face him. However, after his old enemy Kato, now head of the Japan Karate Association, hears about his feats and acts against them, Bae-dal will have to understand the quest of his life is not over yet.
Despite coming from a relatively obscure manga, the film was the seventh highest grossing Korean film of 2004.
This film provides examples of:
- Adaptation Name Change: In the original manga, Oyama is not called by any other name than his Japanese pseudonym. Here he is referred as Choi Bao-dal as his supposed birth name.
- Adapted Out: Many of Oyama's friends and rivals from the manga, which included real life people like Rikidozan, Masahiko Kimura, Jack Dempsey and Great Togo, are all absent from the movie.
- Artistic License History:
- The historical Masutatsu Oyama was born Choi Yeong-eui, not Choi Bao-dal. The latter is somewhat of a popular belief because "Oyama Masutatsu" is a character transliteration of "Baodal", a name for the ancient Korean Joseon kingdom which Oyama chose deliberately.
- In real life, kamikaze missions weren't entrusted to Korean-born pilots. Choi and his pals would have never been punished for refusing, as they would have never been ordered to perform it (nor allowed if they had ever asked to). However, the real Oyama did have Japanese friends who died in kamikaze units, which he recounted as the reason why he often sought to brawl with U.S. soldiers post war.
- The Oyama from the movie is an uneducated worker, while the real deal studied at Waseda and Takushoku, two of the greatest Japanese universities at the time.
- The real Choi never showed any signs of overt Korean patriotism, and actually spent the rest of his life as a Japanese citizen under the name of Oyama, just like he does in the manga. This is a sort of Adaptation-Induced Plot Hole in the movie, as it feels strange that a furiously Korean man like him adopted a Japanese identity so easily.
- Artistic License Martial Arts:
- Most of Oyama's biography from this film is fictitious anyways, but it is notable that he is portrayed here as a practitioner of Korean martial arts (hinted but not stated to be taekkyeon), which the real Oyama was not. He first trained in kung fu, later trained formally in two styles of karate, and ultimately also gained a Judo black belt.
- While it can admittedly be hard to tell apart between karate styles in all-out brawls, Choi's style does not resemble Kyokushin. Even his kata, which are usually very distinctive to each school, are very generic ones.
- The film follows a popular impression that karate was the default martial art of the Empire of Japan, as Kato boasts of it against the foreign fighters in the prisoner camp, and later he and the JKA become very patriotically motivated against Choi because his Korean style. In reality, karate could hardly be considered Japanese for most of its story, as it came from the Ryukyu islands instead of mainland Japan and had strong Chinese influences on its origin. A patriotic Japanese martial at the time of the movie would have been either Judo or any traditional jujutsu school.
- Asskicking Pose: Averted. Choi's favoured stance is a simple boxing-like guard. The few opponents stupid enough to try elaborate stances get unpleasant things done to them. Then subverted; at the end Choi and Kato are so evenly matched that they take a moment's time out to limber up and get into their preferred stances again.
- Asskicking Equals Authority/Authority Equals Asskicking: Justified in that the masters are universally better fighters than their students. However, the fact that General Kato and his lieutenant Ryoma are the only people on Bae-dal's level is a straighter example.
- Big Damn Heroes: When a gang of Yakuza pull swords on Bae-dal, some guy in a hat (later revealed to be an old friend) leaps out of the crowd and fights them to a standstill - despite only having one hand.
- Book-Ends: The fights with Kato. At the start of the film, he loses by punching Kato in the face; at the end of the film, he wins by refusing to punch Kato in the face.
- Canon Foreigner: Ryoma and Kato, among other characters, are original to the film.
- Charles Atlas Superpower: Choi develops improbably powerful fighting technique, strength, and resilience from his mountain training, including the ability to smash rocks and break limbs with a single punch. Surprisingly, this is one of the few things the film gets more or less right, as Oyama really was that good at breaking things (or so says the legend).
- Curb-Stomp Battle: Only the masters pose any kind of threat to Choi; students get dispatched with one or two punches. Interestingly enough, developing enough skill to do this is actually one of the philosophical goals of karate, a concept called ikken hissatsu ("one blow death"). By doing so, Oyama is showing not only that he is a badass, but also that his karate is superior in all senses.
- Decoy Antagonist: The American soldier who sees Choi in his vigilante phase as a personal rival is set up as a villain, but he is dispatched offscreen a few minutes later.
- Heroic BSoD: Happens to Oyama no less than three times: after Bum-soo's death, once through despair in the mountains, and once when he has just killed Ryoma realized that violence has horrible consequences.
- Hoist by His Own Petard/Suicidal Overconfidence: Ryoma is easily the best fighter in the film, and could have effortlessly beaten Choi if he had only not been arrogant enough to toy around with him instead of fighting seriously.
- Important Haircut: After his Heroic BSoD in the mountains, Choi shaves off one eyebrow to make sure he can't return to civilization until it's grown back. Again, this is a traditional act in Japanese culture.
- Let's Get Dangerous!: Kato and Choi both, when they each realise that the other is too tough for the usual curb-stomp to work.
- Made of Iron: Choi's modus operandi. The mountain training was specifically intended to make him able to take any kind of punishment Japan throws at him. Kicks and punches bother him about as much as a stiff breeze.
- Martial Arts Uniform: Choi wears one for most of the second two-thirds of the movie - it is his only clothing while training in the mountains.
- Ninja: One (implied to be one) provides one of his more difficult fights outside a feudal-era Japanese castle. He even does a wall-running stunt while grabbing Choi.
- Peek-a-Bangs: Ryoma. For most of the film, it conceals the fact that he's actually blind in one eye.
- Reality Ensues: You want to have a badass martial arts duel to the death? Expect to be arrested, and to have to deal with the fact you just created a widow and an orphan.
- Roaring Rampage of Revenge: The Koreans go on one after Bum-soo is murdered. Its general ineffectiveness prompts Bae-dal to go on his mountain adventure.
- Scry vs. Scry: Subverted. Before the duel with Ryoma, he has a vision of the katana-wielding rival being stopped before he can unsheath his sword and then losing. When they do fight, however, the rival is able to draw his katana fast enough to lay it flat on his opponent's head, showing that he could have easily won. Then they fight for real.
- 10-Minute Retirement: After killing Ryoma, Choi puts his gi aside and swears never to fight again. This doesn't last very long.
- Training from Hell: Learning to take any punishment, by taking every punishment.
- Very Loosely Based on a True Story: Calling this film historically inaccurate is the height of understatement - about the only things that are accurate is that Choi (Yeong-eui, not Bae-dal) was a Korean, who became a fighter pilot, who became a Made of Iron karate master. Most of the characters are completely fictional, and many events of the real Choi's life are distorted or skipped over. Ironically, the manga in which it is based might be actually considered more faithful to the real story, if anything because it contradicts it less often.
- Worthy Opponent: Choi's true victory is when Kato finally recognizes him as this.
- Yamato Nadeshiko: Youko, Bae-dal's lover, is a maiko (geisha-in-training), wears kimono in all her appearances, and lives a relatively traditional lifestyle. In fact, she is shown to wear Western clothing only once in the entire film.