Kagemusha

Kagemusha , Shadow Warrior? is a 1980 film by Akira Kurosawa. In Japanese, kagemusha lit. shadow warrior is a term used to denote a political decoy. It is set in the Sengoku period of Japanese history and tells the story of a lowerclass criminal who is taught to impersonate a dying daimyo in order to dissuade opposing lords from attacking the newly vulnerable clan. The daimyo is based on Takeda Shingen, and the film ends with the climactic 1575 Battle of Nagashino.

Shingens army has besieged a castle of Tokugawa Ieyasu. When Shingen visits the battlefield to hear a mysterious nightly flute player, he is shot by a sniper. Mortally wounded, he orders his generals to keep his death a secret for three years. Shingen later dies while being carried over a mountain pass, with only a small group of witnesses.Nobukado presents the thief to Shingens generals many of the renown TwentyFour Generals of Takeda Shingen, proposing to have this kagemusha impersonate Shingen fulltime. At first, even the thief is unaware of Shingens death, until he tries to break into a huge jar, believing it to contain treasure, and instead finds Shingens preserved corpse. After this act, the generals decide they cannot trust the thief and set him free. ........

Source: Wikipedia