You may submit multiple charts to a certain song. In spite of allowing of single chart, songs which have multiple charts are recommend, for players having different skill level can enjoy the song.
Duplicate song page is not welcomed since the charts of the same song could be made by different creators.
All the songs have any stable chart must involves a stable chart lower than Lv.10.
Audio used in chart should be OGG format.
Incorrect meta info like Title and Artist is not allowed.
Incorrect BPM and offset is not allowed.
Ambiguous chart name which cannot describe the play mode or difficulty appropriately is not allowed.
Offensive or discrimination content is not allowed.
Unreasonable note count : inadequate or overabundance is not allowed.
The length of the chart must above 60 seconds.
The bitrate of the audio shouldn't be higher than 192kbps.
A set of difficulty at least should have 2 charts. One of the set should lower than Lv.10.
The level of the chart should represent the difficulty of the chart.
Chart shouldn't have two notes at the same time and same column.
Notes should represent the song. Overchart is not recommended.
Auto Mod should get a full score in the normal condition.
If there's huge problem in your chart during stable process, your chart may back to "Alpha" status.
Assistants can promote your chart to "Beta" status, but your chart may back to "Alpha" status if quality is not enough.
Before stable, please add the key amount and other related tags to the song tag. And add simple metadata information to description. The metadata information should contain artist, lyric (if possible), and source.