Measure 10 of the Moonlight- Going from Couch to Concert Hall One Measure at a Time

This measure starts in the key of e minor. The natural sign before the first g lasts until the end of the measure and has to be rewritten in the next measure for the sound to continue. 

One of the most common errors of inexperienced pianists is getting confused about the rules of the sharps, flats, and natural signs written in both the key signature, and in the music. 

Happy Playing!