|This article is about a/an episode in Kamen Rider Den-O.|
Fighting Style (ケンカのリュウ儀 Kenka no Ryūgi) is the twenty-first episode of Kamen Rider Den-O.
Ryutaros grows jealous of Yuto due to his connection to Airi, making him take drastic action in order to take him down!
As Ryotaro saw the actual Yuto Sakurai in the past, he becomes suspicious of the one that is Zeronos. After telling the Owner of the battle in 2006, he states that he believes that Yuto may be the Yuto Ryotaro knows, from 10 years in the past. Hana, herself, wishes to know more about how the ZeroLiner can exist when its timeline was destroyed, much like her own timeline was. Meanwhile, Yuto injures his hand and goes into the Tokyo of 2007 and Deneb possesses him to assist a young man named Tanaka sell goods for the Tanabata Festival.
After warning Deneb not to do things on his own, he leaves the Imagin to take care of things, by selling the items while in a tiger costume. In Tanaka's dream-like state, he opens a contract with the Tortoise Imagin to get even with his employer. At the Milk Dipper, Ozaki and Issē fight over putting tags on the Tanabata Tree while Airi serves coffee to Yuto, who introduces himself to her. On the DenLiner, Ryutaros has been drawing, and attacks anyone who steps on any of the drawings, one of which depicts Den-O Gun Form shooting Zeronos, to Urataros' dismay. When Kintaros gives Ryutaros the idea to show his strength to impress Airi, he possesses Ryotaro, who had been in the Milk Dipper with Hana, at the time.
Once Yuto leaves, Ryutaros takes control and follows, cornering him with his dancers. As Ryutaros pursues Yuto, the Tortoise Imagin and its rabbit half attack Tanaka's employer to complete the contract. Hana tells Yuto to transform and that Ryotaro cannot control Ryutaros, but he reveals that the times he can transform into Zeronos is limited. He eventually gives in and fights Den-O Gun Form while Deneb runs to his partner's aid.
Both Zeronos Altair Form and Den-O Gun Form are equally matched, as they rush at each other on their respective motorcycles.
- Den-O: Gun Form
- Zeronos: Altair Form
- Ryotaro Nogami (野上 良太郎 Nogami Ryōtarō): Takeru Satoh (佐藤 健 Satō Takeru)
- Hana (ハナ Hana): Yuriko Shiratori (白鳥 百合子 Shiratori Yuriko)
- Yuto Sakurai (桜井 侑斗 Sakurai Yūto): Yuichi Nakamura (中村 優一 Nakamura Yūichi)
- Naomi (ナオミ Naomi): Rina Akiyama (秋山 莉奈 Akiyama Rina)
- Airi Nogami (野上 愛理 Nogami Airi): Wakana Matsumoto (松本 若菜 Matsumoto Wakana)
- Seigi Ozaki (尾崎 正義 Ozaki Seigi): Akira Nagata (永田 彬 Nagata Akira)
- Issē Miura (三浦 イッセー Miura Issē): Ryo Ueno (上野 亮 Ueno Ryō)
- Momotaros (モモタロス Momotarosu, Voice): Toshihiko Seki (関 俊彦 Seki Toshihiko)
- Urataros (ウラタロス Uratarosu, Voice): Kōji Yusa (遊佐 浩二 Yusa Kōji)
- Kintaros (キンタロス Kintarosu, Voice): Masaki Terasoma (てらそま まさき Terasoma Masaki)
- Ryutaros (リュウタロス Ryūtarosu, Voice): Kenichi Suzumura (鈴村 健一 Suzumura Ken'ichi)
- Deneb (デネブ Denebu, Voice): Hōchū Ōtsuka (大塚 芳忠 Ōtsuka Hōchū)
- Owner/Opening Narration (オーナー／オープニングナレーション Ōnā/Ōpuningu Narēshon ): Kenjirō Ishimaru (石丸 謙二郎 Ishimaru Kenjirō)
- Tanaka (田中): Yusuke Shoji (少路 勇介 Shōji Yūsuke)
- Iijima (飯島): Hiroaki Matsuzawa (松澤 仁晶 Matsuzawa Hiroaki)
- Dancer: Yujiro Sasaki (佐々木 友司朗 Sasaki Yūjirō), Ryo Sasaki (佐々木 亮 Sasaki Ryō), Tomoaki Kitamura (北村 智晃 Kitamura Tomoaki), Kazunori Masaki (正木 和宣 Masaki Kazunori), Takayuki Taniguchi (谷口 隆之 Taniguchi Takayuki), Ryuichi Kato (加藤 竜一 Katō Ryuichi)
- Tortoise Imagin (トータスイマジン Tōtasu Imajin, Voice): Kōji Ochiai (落合 弘治 Ochiai Kōji)
- Kamen Rider Den-O/Momotaros: Seiji Takaiwa (高岩 成二 Takaiwa Seiji)
- Urataros: Eitoku (永徳 Eitoku)
- Kintaros: Jirō Okamoto (岡元 次郎 Okamoto Jirō)
- Ryutaros: Toshihiro Ogura (おぐら としひろ Ogura Toshihiro)
- Kamen Rider Zeronos: Makoto Ito (伊藤 慎 Itō Makoto)
- Deneb: Yoshifumi Oshikawa (押川 善文 Oshikawa Yoshifumi)
- Tortoise Imagin: Jun Watanabe (渡辺 淳 Watanabe Jun)
- As part of Super Hero Time, this episode aired alongside Juken Sentai Gekiranger episode 18, Lesson 18: Shakkin-Kīn! The Body is Strong.
- Viewership: 7.1%
- The title of the episode is a pun due to "style" being stated as "Ryuugi" in Japanese, with "Ryuu" in katakana as in "Ryutaros", thus it ends up translating as "Ryu's Style of Fighting".
Blu-ray Box 2 comes with 18 episodes.