Regardless of the music, Rachmaninoff always planned his performances carefully. He based his interpretations on the theory that each piece of music has a "culminating point." Regardless of where that point was or at which dynamic within that piece, the performer had to know how to approach it with absolute calculation and precision; otherwise, the whole construction of the piece could crumble and the piece could become disjointed. This was a practice he learned from Russian bass Feodor Chaliapin, a staunch friend. Paradoxically, Rachmaninoff often sounded like he was improvising, though he actually was not. While his interpretations were mosaics of tiny details, when those mosaics came together in performance, they might, according to the tempo of the piece being played, fly past at great speed, giving the impression of instant thought.