Lesson 18: Shakkin-Kīn! The Body is Strong

'''Shakkin-Kīn! The Body is Strong''' is the eighteenth episode of Juken Sentai Gekiranger.

Synopsis
It is revealed that Geki Shark is possessed by Dokariya, and it takes an attack from Bat Li and Elehung to tell the Gekirangers to use Geki ElephanTohja to defeat Geki Shark for the time being. The two Kensei berate Sharkie, because they feel that he was not up to the task of teaching a student due to his ideals of a strong body being foolish, before Xia Fu arrived and suggested that they all go back to the group's campsite to try and continue the training. Sharkie tries to impress Elehung and Bat Li, but they further scold Sharkie's ideals, and he leaves, disheartened as he renounces Jyan as his student out of failing him. That night, someone uses one of Sharkie's swords to attack Xia Fu, and Miki assumes that it must be Sharkie, with Bat Li, Elehung, and the Gekirangers pursuing him. The next morning, the two Kensei, Retu, and Ran find/capture Sharkie, while Miki and Xia Fu clean up the campsite. While Xia Fu is distracted, Miki picks up one of tent's pins and charges at him, only to be stopped by Jyan who knew something was wrong all along. Dokariya reveals himself after being defeated in Miki's body by Xia Fu and then jumps into Jyan to use him to kill Xia Fu as Rageku wished. However, Jyan overpowers the Hermit Crab-Ken user and forces him out of his body, revealing that Sharkie's training allowed him to overcome the Ringi. Jyan then uses the techniques Sharkie taught him to defeat Dokariya with the Geki Waza Wave-Wave Slash. Dokariya then enlarges and jumps into the sea. But Geki Tohja follows by summoning Geki Shark and combine to form Geki SharkTohja. The battle underwater ends with Geki SharkTohja's Great Firm-Firm Slash destroying Dokariya. After the battle, Xia Fu approves of Sharkie as a true master, bringing the Kensei to tears. Back at the Rin Jū Hall, Rio reveals his one true rival to Rageku: a man with a "White Tiger" Geki named Byakko.