Necessity in man. What is "unfree will"?

Since free will is discussed, it must obviously be some restricted reality (if "freedom" meant "everything," there would be no need for a separate word). What follows? That there must be events external to one's freedom: therefore, besides "free will" there should also consequently be "unfree will." Although Nietzsche considers both terms entirely fictional, he gives some clues about the psychological reality behind them:
In short, an unexpected change. Now, going back to the mentioned definition, chance means: that what cannot be predicted. If randomness affects a man (unsubjugated, reaching even the surface of his consciousness), then "unfree will" occurs. Thus, whenever we call something free, we feel something free, in short: wherever we feel our power, it is deterministic, it is a necessity. And indeed Nietzsche says it with the mouth of Zarathustra:
Out into distant futures, which no dream hath yet seen, into warmer souths than ever sculptor conceived, — where gods in their dancing are ashamed of all clothes: (...)
Where all time seemed to me a blessed mockery of moments, where necessity was freedom itself, which played happily with the goad of freedom:

The same in Beyond Good and Evil: