|(血之池一族, Chinoike Ichizoku)|
|Novel||Sasuke Shinden: Book of Sunrise|
|Appears in||Anime, Novel|
During the Warring States Period, the Chinoike were one of the many mercenary ninja clans active in the Land of Lightning. At some point, a woman of the Chinoike clan married the Land of Lightning's daimyō. The daimyō's first wife became jealous of her, and when the daimyō died soon after their marriage the first wife blamed the woman and her clan for the daimyō's death. Many believed the first wife's lies, causing the entire Chinoike clan to be banished from the country. The Uchiha clan were hired to carry out this task, and they forced the Chinoike clan to settle in the Valley of Hell in the Land of Hot Water.
The Valley of Hell was thought to be uninhabitable. Ninja from the nearby Yugakure checked in on the Chinoike clan a few months after they were relocated to the valley and found them drinking what appeared to be blood; it was actually only water, turned red by minerals in the earth. Unwilling to investigate further, Yugakure declared the Valley of Hell off limits. Over the years, the valley's location was forgotten and the Chinoike clan faded from history. In truth, the Chinoike were able to survive, surviving off the valley's minimal wildlife and resources and enjoying decades of peace.
Though living peacefully, the Chinoike clan had their disagreements. Being forced to live so closely together for so long caused even minor arguments to erupt into violence; in the anime, the tipping point was whether or not the clan should seek vengeance against the Uchiha clan for exiling them there. In a single night, the clan wiped themselves out, with only En Oyashiro and his daughter, Chino, surviving. They left the valley and Oyashiro, guilty for his role in the deaths of his clansmen, decided to hide his identity from Chino, raising her to believe that she was the last of her family in the hopes that she would not repeat his mistakes.
Shortly after the deaths of the Chinoike clan, the Valley of Hell was rediscovered by Hidan. He reported this to Yugakure, who travelled there and confirmed that there was nobody still alive in the valley. They once again declared the valley off limits and officially ruled the Chinoike to be extinct.
The Chinoike are famous for their Ketsuryūgan, a dōjutsu that, when active, makes their eyes appear blood-red. The Ketsuryūgan allows them to perform powerful genjutsu, of comparable strength to the Uchiha clan's Sharingan. They can also use the Ketsuryūgan to manipulate liquids that have high iron contents, such as blood or the water that naturally flows in the Valley of Hell. Before they can manipulate such liquids, it is necessary that they imbue it with their own chakra.
- "Chinoike" (血之池) literally means "blood lagoon".