In which book volume did Kakashi start covering his eye?

Kakashi has had his Sharingan Eye covered long before he is brought into by the manga. He obtained that eye as a ninja trainy after his comrade obito was crushed by falling rocks, as a gift obito gave him his eye before he died. Kakashi has been forced to cover it ever since unless in use otherwise he would run out of chakra and without it he could no longer use jutsu.