We mainly request that you submit Kagamine songs that you will feel comfortable creating fan art or writing of.

Solo songs are welcome submissions, as there are many songs out there that feature either Rin and Len as the main vocal, but may have the other included in the PV, song's story, or sequels (for example, mothy's Daughter of Evil, or TravoltaP's Soleil). We decided to include cover songs as well, since some of their covers are quite iconic - like Electric Angel.

The consensus we came to is that - as long as your final piece can depict both Rin and Len, and is inspired by/based on an existing Kagamine song - we will not restrict solos/covers from being submitted. The same goes for songs without official PVs or designs; if a participant feels comfortable coming up with their own "designs" or "depictions" of Rin and Len for a song without a PV, we won't stop them.

I hope this clears up the confusion!