Sentence:  Every detail in his interpretation has been beautifully thought out , and of these I would especially cite the delicious landler touch the pianist brings to the fifth <WSD>variation</WSD> ( an obvious indication that he is playing with Viennese musicians ) , and the gossamer shading throughout . 
Meaning of the word marked with <WSD> tags:  a repetition of a musical theme in which it is modified or embellished