History Recap / BatmanTheAnimatedSeriesE44DayOfTheSamurai

* DeducingTheSecretIdentity: Discussed in this episode, when Batman tells Alfred that his old training rival Kyodai Ken is certain to have deduced that Bruce Wayne and Batman are the same person via FightingFingerprint.

* TattooedCrook: Kyodai has a ''huge'' tattoo of a Japanese demon's head on his back. While a tattoo isn't a sure sign of being a criminal in the west, in Japan it's virtually a guarantee due to their cultural taboo against them, especially with tattoos of that size. However, we saw in the last episode that it's the same tattoo Yoru Sensei has. It's the mark of the Fang.

* SequelEpisode: To "[[Recap/BatmanTheAnimatedSeriesE35NightOfTheNinja Night of the Ninja]]."

* SurprisinglyRealisticOutcome: Turns out you can't leave a paper scroll untouched for hundreds of years and expect it to not crumble to dust the second it's moved.

** Kyodai Ken steals a scroll in Japan that teaches him the secret of a "deadly touch" technique. When Batman faces him off in the end, he tries to avoid being touched by him in a specific spot, which (theoretically) would [[TouchOfDeath cause instant death]]. He fails and is struck, and seemingly falls dead. He then gets up and continues the fight, eventually besting the ninja. When asked if the technique had missed somehow, he pulls out a metal plate from under his suit, which has been deformed by a strong force.
** Emphasis on "forbidden", even the guardians of the scroll, or specifically, the scrolls location, have never read it for fear of being tempted into using it. It becomes an issue when Bruce's sensei, the current guardian, can't help him with protecting himself from the TouchOfDeath because he doesn't know how it's performed.

-->'''Bruce:''' Fighting styles are like finger prints. He's fought both Bruce Wayne and Batman. He knows we're the same man.

* MartialArtsUniform: Kairi wears her gi through the entire episode because Kyodai kidnaps her while she's training alone.

* OffModel: This is considered by the crew to be one of the worst animated episodes of the series. Part of that has to do with the fact that the original animation studio, Lapiz Azul, went bankrupt during production. The rest of the episode, and its retakes, had to be done by Creator/JadeAnimation instead.

** During a conversation with Alfred, Bruce reveals that Kyodai Ken can pull this--evidently, "fighting styles are like fingerprints," and since Kyodai has [[Recap/BatmanTheAnimatedSeriesE35NightOfTheNina fought both Bruce Wayne and Batman]], [[WhamLine he's worked out that they're the same guy]] by examining their fighting technique.

** During a conversation with Alfred, Bruce reveals that Kyodai Ken can pull this--evidently, "fighting styles are like fingerprints," and since Kyodai has fought both Bruce Wayne and Batman, [[WhamLine he's worked out that they're the same guy]] by examining their fighting technique.

* GoneHorriblyRight: The martial art of Kiba no Hoko (The Way of the Fang) uawa precise strikes against pressure points. The style is so lethal, the man who created it decided it was too dangerous for anyone to use.

* MyGodWhatHaveIDone: The martial arts master who originally created a style called Kiba no Hoko (The Way of the Fang) quickly came to regret it.

* DangerousForbiddenTechnique: Kyodai Ken steals a scroll in Japan that teaches him the secret of a "deadly touch" technique. When Batman faces him off in the end, he tries to avoid being touched by him in a specific spot, which (theoretically) would [[TouchOfDeath cause instant death]]. He fails and is struck, and seemingly falls dead. He then gets up and continues the fight, eventually besting the ninja. When asked if the technique had missed somehow, he pulls out a metal plate from under his suit, which has been deformed by a strong force.

* PressurePoint: The episode revolves around a martial art called Kiba no Hoko (The Way of the Fang), which uses precise strikes against pressure points. Batman's foe, [[TheRival Kyodai Ken]] learned its most fatal technique, the [[TouchOfDeath Oonemuri Touch]].

* DistressedDamsel: Kairi Tanaga, abducted by Kyodai Ken to serve as a [[HostageForMacguffin bargaining chip for the map to the Onemuri Touch]]. But to her credit, she ''does'' try to fight off Kyodai the moment she gets a chance.

* FightingFingerprint: This episode is the TropeNamer.

* HostageForMacguffin: Kyodai forces Batman to give him the forbidden knowledge of the secret technique in exchange for Kairi's life.

* TattooedCrook: Kyodai has a ''huge'' tattoo of a Japanese demon's head on his back. While a tattoo isn't a sure sign of being a criminal in the west, in Japan it's virtually a guarantee due to their cultural taboo against them, especially with tattoos of that size.

* WouldHitAGirl: Kyodai Ken, natch, though it's downplayed, since she's Yoru Sensei's daughter.

* GratuitousJapanese: Kairi’s one line of dialogue in the episode.

* CallForward: Kairi Tanaga, Yoru's star pupil whom Kyodai Ken kidnaps, later appears as an old lady and sensei in ''WesternAnimation/BatmanBeyond''.