is a ninja who appears in kōdan narrative art and fictional writings. The nickname is generally believed to have been concocted from Meiji to the Taishō period. Some argue he is based on real live personages, such as and . His family name, meaning "monkey jump", is written with two kanji; saru (猿) is the character for "monkey", and tobi (飛) is the character for "jump". He was known for his monkey-like agility and quickness, especially in trees. Many depictions portray him as having been orphaned and raised by a band of monkeys, therefore giving rise to the monkey-like abilities. He has been described as a superhero ninja, and caused a boom of ninjas in popular culture during the 1910s-1920s in Japan. In folklore Sasuke is commonly listed as the leader of the Sanada Ten Braves, a fictional group of ten ninja that supposedly assisted the warlord Sanada Yukimura at the battles of Osaka Castle during the final phases of the Japanese civil war era, and he is by far the best known and most popular among them. When appearing with Kirigakure Saizō, one of his fellow Ten Braves, he is often thus contrasted with his best friend/arch-rival, who usually has an elegant, or at least clean-cut, appearance and magic-like ability. Sasuke is generally said to be a Kōga ninja, whereas Saizō is an Iga ninja. As such, when the two appear together, they are almost always depicted as arch-rivals and later, after being recruited to the Sanada cause, best friends. (This rivalry parallels the Iga-Kōga rivalry and the Hattori-Fūma rivalries in ninja fiction.) It is said he fell in battle against the forces of Tokugawa Ieyasu during the Siege of Osaka in the summer of 1615; but there is no historical record of this. In another version, Sasuke infiltrated Tokugawa Ieyasu's stronghold during 1615 and, having caught his foot in a bear trap while escaping the enemy, cut it off at the ankle to escape and then took his own life rather than be captured. In popular culture Sarutobi Sasuke's image has been very influential in ninja fiction, in which he is usually portrayed as a young boy. The character was immortalized in contemporary Japanese culture by the popular Tachikawa Bunko (Pocket Books) children literature between 1911 and 1925, as well as in Sarutobi Sasuke, one of the more famous gag manga by Shigeru Sugiura from the 1950s (followed