Most primary school children prefer the simplicity of the 4-hole Oc® . The first 40 tunes in Play your Ocarina books are just played on the top four holes. A 4-hole ocarina is sufficient for Book 1 and Book 2, and for many of the tunes in Carols and Songs of Praise. If your children are older, are very musical, or want to progress to Book 3 and Book 4, then the thumb-holes of the 6-hole ocarina are useful for the extra notes.