You can have no more than one song in one particular genre or sub-genre.

Say you have all your songs in the
» main genre HipHop, evenly divided between 'Bass Rap' and 'Spoken Word' as sub-genre.

Then your
» strongest song will appear on the HipHop charts, because all your songs have HipHop as main genre.

» The strongest song within the sub-genre 'Bass Rap' will appear in that sub-genre charts, and the
» strongest 'Spoken Word' song will appear on the 'Spoken Words' sub-charts.

In addition, please note the cover songs are not eligible for the main genre charts.