Katsuyori thus decides to test the kagemusha in front of the council, as the majority of the attendants are not aware that Shingen is dead. However, Katsuyori is incensed by his father's decree of the three year subterfuge, which delays his inheritance and leadership of the clan. When the kagemusha must preside over a clan council to plan how to respond to provocative attacks made by Tokugawa against Takeda border castles, he is instructed by Nobukado to not speak until Nobukado brings the generals to a consensus, whereupon the kagemusha will simply agree with the generals' plan and dismiss the council. By imitating Shingen's gestures and learning more about him, the kagemusha begins to uncannily mimic the persona of Shingen, and even convinces Takeda Katsuyori's son and Shingen's grandson, who was very close with Shingen. Returning home, the kagemusha successfully fools Shingen's retinue. Although they suspect that Shingen has died, they are later convinced by the kagemusha's performance. The spies follow the Takeda army as they march home from the siege. The Takeda clan preserves the deception by announcing that they were making an offering of sake to the god of the lake. The thief, however, overhearing the spies, goes to offer his services, hoping to be of some use to Shingen in death. Spies working for Tokugawa and his ally Oda witness the disposal of the jar and, suspecting that Shingen has died, go to report the death. Later, the Takeda leaders secretly drop the jar with Shingen's corpse into Lake Suwa.

The generals then decide they cannot trust the thief and set him free. At first, even the thief is unaware of Shingen's death, until he tries to break into a huge jar, believing it to contain treasure, and instead finds Shingen's preserved corpse. Nobukado presents the thief to Shingen's generals, proposing to have this kagemusha impersonate Shingen full-time.

Meanwhile, Shingen's rivals Oda Nobunaga, Tokugawa Ieyasu, and Uesugi Kenshin each contemplate the consequences of Shingen's withdrawal of his army still not knowing of his death. Shingen soon dies with only a small group of witnesses.

Mortally wounded, he orders a withdrawal and commands his generals to keep his death a secret for three years. One evening when Shingen visits the battlefield he is shot by a sniper who has mapped Shingen's previous movements in the camp.

Later, Shingen's army has besieged a castle of Tokugawa Ieyasu. The brothers then agree that he would prove useful as a double, and they decide to use the thief as a kagemusha, a political decoy. In Japan's Sengoku period, Takeda Shingen, daimyō of the Takeda clan, meets with his brother Nobukado, and an unnamed thief whom the latter met by chance and spared from crucifixion due to the thief's uncanny resemblance to Shingen.

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