"The piano doesn't sustain sound. Left alone, the sound attenuates and disappears. Perpetual sound is... essentially the opposite of piano, because the notes never fade. I suppose in literary terms, it would be like a metaphor for eternity."
In confronting his (and our) mortality, Ryuichi Sakamoto meditates on the perpetuity of music that overlays the finality to his existence.
"Music... requires peace."
Sakamoto finds a special purity in the trees as he wanders the forest, in the ice caves as he peers under glaciers, in a Tsunami-surviving piano left "retuned by nature", absorbing the world as his soundstage.
Such is an artist's mind.