All rules are considered final and may not be broken under any circumstances.
- All single-gamemode mapsets must include a spread of at least two difficulties. The lowest difficulty must be at least a Normal (as per the ranking criteria for the applicable gamemode).
- Multi-gamemode (aka: hybrid) mapsets without osu! difficulties must also have a difficulty spread of at least two difficulties per gamemode. As above, the lowest difficulty must at least be a Normal and it must adhere to all difficulty-specific guidelines.
- If a multi-gamemode (hybrid) set includes any osu! difficulties, it must:
- Contain a spread of at least two difficulties. Again, the lowest must be a Normal which adheres to difficulty-specific guidelines for the gamemode.
- Respect difficulty spread with gamemode conversion in mind. For example, a mapset with Easy and Normal osu! difficulties and an Insane osu!catch difficulty is not allowed - a Hard difficulty would need to be made to bridge the gap.
- Have any present osu!catch difficulties modeled around the existing set's converted spread. Given that osu! cleanly converts across to osu!catch, this is an extension of the above rule. The lowest osu!catch difficulty must be at least Insane in difficulty.
- Have any present osu!taiko or osu!mania difficulties arranged into a reasonable spread. The lowest difficulty must be at least a Hard.
- Mapsets must have a minimum drain time of 30 seconds. This is to ensure each ranked map has a practical play-time.
- For a map to be considered as a Marathon, it must have a minimum drain time of 5 minutes. Marathon sets are exempt from difficulty spread requirements.
- Songs cannot be altered to reach the minimum drain time requirements. These limitations exist to facilitate high-quality, high-effort mapsets. Types of abuse include:
- Lowering a song's BPM
- Looping portions or segments of a song
- Adding sounds before or after the song begins or ends
- Extending sliders or spinners over inaudible sounds
- Manually removing breaks
- Mapsets are limited to 8 total difficulties of a single gamemode. The highest difficulty of a particular gamemode within a set is always exempt from the reasonable spread requirements.
- A difficulty's name must accurately indicate its actual level of difficulty. The hardest map in a gamemode's set is exempt from this rule, but difficulty names should otherwise always reflect their actual difficulty.
- A difficulty's name must remain relevant to the overall set. Guest difficulties may be named to indicate their creators (e.g: Guest Mapper's Insane). Additionally, the uploader of a mapset must NOT name any difficulties to indicate their own involvement, except where it conflicts with existing metadata.
- A mapset's host (uploader) must have equal or more drain time mapped than any guest difficulty mappers. This is to award credit where credit is due. Drain segments within a collaborative difficulty must be listed in the beatmap's notes, or via storyboarding.
Guidelines may be reviewed for exemption under exceptional circumstances and with ample explanation.
- Aim to keep difficulty names clear and meaningful. Combining usernames in esoteric combinations means nothing to anyone bar the people involved in the set. Simplification is always recommended.
- Avoid adding extra elements to difficulty names that aren't related to either the difficulty's creator or a level of difficulty. An example of this would be "Mapper's Tragic Love Extra". The hardest difficulty in a set may always use free naming, but it should almost always refer to the song in some way or another.
- Keep nicknames for guest difficulty creators consistent across sets. Mappers with multiple nicknames across sets will confuse players into thinking they may be separate or unrelated people.
- Avoid using unicode characters in a difficulty's name. These may cause issues with the Beatmap Submission System and problems for users who are linking them in chat.