in one of the movie's scenes involving takeda shingen's young grandson takemaru, shingen's bodyguard sohachiro tsuchiya and the kagemusha, there was this following dialogue:
Takemaru: Why are you called a mountain, grandfather?
Kagemusha: [Unaware of the legend behind Shingen's nickname] "Mountain"? Takemaru: Everybody calls you that. Where is the mountain? Is it because we have this mountain in our garden?
Sohachiro Tsuchiya: [Quickly intervening to cover for Kagemusha's ignorance] You know the master's banner. What is printed there?
Takemaru: [Reciting the slogan on the Takeda clan's banner] Swift as the wind... Quiet as a forest... Fierce as fire... Immovable as a mountain.
Sohachiro Tsuchiya: The lord is that mountain. Both in battle and at home, he is steadfast, like a mountain. When his army advances, first the horsemen attack, swift as the wind. Second, the lancers raise a forest of spears, advancing with silent resolve. Third, more horsemen engulf the enemy ranks, as mercilessly as fire. And the lord is always behind them, watching over them, immovable as a mountain. That is why our army, from general to foot soldier, can fight so resolutely... Immovable as a mountain. The lord is that mountain. So we call him "the mountain."