One practical method of tuning the piano begins with tuning all the notes in the "temperament" octave in the lower middle range of the piano. A tuner starts by using an external reference, usually an A440 tuning fork, (or commonly a C523.23 tuning fork) to tune a beginning pitch, and then tunes the other notes in the "temperament" using tempered interval relationships. During tuning it is common to assess fifths, fourths, thirds (both major and minor) and sixths (also major and minor), often playing the intervals in an ascending or descending pattern to hear whether an even progression of beat rates has been achieved.