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Developer(s) Dean "peppy" Herbert
Platform(s) Microsoft Windows
Android (starting 2.1)
iOS (App Store)
Windows Phone
Release date(s) September 16, 2007
Genre(s) Music (Rhythm)
Mode(s) Singleplayer, Multiplayer

osu! is a freeware rhythm game originally for Microsoft Windows. It is written in C# on the .NET Framework. The game has also been ported to OS X, iOS, Android, and Windows Phone.[1] Its gameplay is based on commercial titles including Osu! Tatakae! Ouendan, Elite Beat Agents, Taiko no Tatsujin, beatmania IIDX, O2Jam, and DJMax.


Game levels are called beatmaps. In each beatmap, a song will play and different rhythmic hit elements (hit circles, sliders and spinners) will appear on the play field. Players must use a pointing device to manipulate these elements in time with the playing song's rhythm in order to earn points. The use of a graphics tablet in combination with a keyboard is common in osu!, although some players do use a mouse. Very few use a Tablet PC for playing osu with.


There are five default difficulties which are easy, normal, hard, insane, and extra. There is also a marathon tag that means maps tagged with this are over five minutes of drain time, and a "TAG2/TAG3/TAG4" difficulty that means maps which must be played by two, three, or four people in a rotating state. Content creators, beatmap designers can also give their own names for their difficulties.


The main objective when playing osu! is simply for players to hit, complete, and clear enough hit circles, sliders and spinners to keep their health bar, which drains at a steady rate throughout the game, above 0 until the song is over. More experienced players will often strive for a more specific and difficult goal, like improving their high score or grade on a particular map, usually by attempting to time their hits better and avoid as many misses as possible to increase combo multipliers.

A hit circle as it appears in osu!.

Hit circles[edit]

Also sometimes referred to as notes, hit circles are a common object on nearly every beatmap. When a hit circle appears, a ring, called the approach circle, will appear around it and begin to shrink. In order to score points from a hit circle, players must place their cursor over the circle and click the hit button as the approach circle touches the edge of the hit circle.


Sliders appear as two hit circles with a solid path, called a slider track, between them. As with hit circles, an approach circle appears at the beginning of a slider track, which must be clicked when the approach circle touches its edge. Unlike hit circles, however, after the start of a slider has been hit, a ball, called the slider ball, will begin to roll along the slider track, and players must continue to hold down the hit button and keep their cursor hovered over or near the slider ball until it has reached the end of the slider. Sometimes a slider end will have an arrow, called the reverse arrow, which means the player will be required to follow the slider ball back to its starting point.


A spinner is a large circle that takes up most of the play field when it appears. A ring like the approach circle of hit circles and sliders will also appear and begin to close on the spinner's center. Players must hold down the hit button and spin their cursor around the center of the spinner. As players continue to spin, the spinner gauge at either side of the screen begins to fill, and once it has been filled, the player will be notified that the spinner has been cleared. Continued spins after this and until the ring reaches the spinner's center will award bonus points.

In the new version the approach circle is replaced by the changing of the color of the border of the spinner that gradually fades to red as the spinner approaches the end. The gauge is also absent.

Hits and misses[edit]

Hit circles, sliders, and spinners have different criteria to how they can be hit or missed, and to how points can be gained.

Clicking the hit button at the right time while the cursor is hovered over a hit circle or the start of a slider, or clearing a slider will earn a player points. In the case of hit circles, the points awarded are completely dependent on the timing of the hit. Sliders are generally considered more lenient, and as long as a player doesn't hit the start far too early or too late, collects all the slider ticks, and continues to hold the hit button and hover the cursor over the slider ball until it reaches the end, a maximum number of points are earned. The points awarded by a spinner are dependent on the number of spins completed. Additional spins after a spinner has been cleared will further increase the points earned. Successful hits will fill the health gauge a small amount.

No points are earned when an object has been missed. Hitting a hit circle too early or too late, failing to collect any slider ticks, or failing to fill the spinner gauge an adequate amount will result in a miss being added to a player's score. A miss, or missing a slider tick or end, causes the health gauge to drop an amount.


A combo multiplier is kept throughout the song. Upon successfully following an object (hitting a hit circle, hitting a slider end or slider tick, clearing a spinner, etc.), the multiplier is increased by 1; upon a failure (missing a hit circle, clicking slider start way too early, missing a slider start or slider tick, or not filling a spinner an adequate amount), the multiplier is reset to 0; combo multiplier is not increased nor reset to 0 by missing a slider end or receiving 1,000 bonus from spinner. This multiplier is then multiplied by several factors including the difficulty of the played beatmap and "mod multiplier", user-applicable multiplier resulting from activating gameplay-altering mods, which is then multiplied by the base score of the hit to get the score of the hit. To be more precise, the score formula of a hit is:

Score of a hit = Base score of a hit + Base score of a hit * (Combo multiplier * Difficulty multiplier * Mod multiplier) / 25

Base score of a hit The hit circle judgement (50, 100 or 300)
Combo multiplier (Combo before this hit - 1) or 0, whichever is higher
Difficulty multiplier The difficulty setting for the beatmap
Mod multiplier The multiplier of the selected mods

Additionally, each slider start, end, and repeat tick awards 30 points, each slider middle tick awards 10 points and each spin of a spinner awards 100 points. Player is also awarded with additional bonus of 1,000 points for each spin of a spinner after the spinner meter is full.


osu! has several difficulty modifiers that can alter the gameplay. These mods are categorized into four groups:

Difficulty reduction[edit]

These mods reduce the difficulty (for example, by disabling failing so a player can play even when the health bar reaches zero), but at the expense of reducing the score multiplier.

  • Easy (commonly abbreviated as EZ) reduces the approach rate, overall difficulty, HP drain and increases the circle size. Also, the player is given three lives; that is, when the HP bar is exhausted, the game pauses and it refills up to two times. This mod reduces the score by 50%.[2]
  • No Fail (commonly abbreviated as NF) makes the player incapable of failing at an expense of 50% of the score.[3]
  • Half Time (commonly abbreviated to HT) decreases the BPM to 75% of its original value, and increases length of the song by 33%, while reducing the score to 30%.[4]

Difficulty Increase[edit]

These mods increase the difficulty of the map in various ways, and reward the player with an increased score.

  • Hard Rock (commonly abbreviated as HR) increases the Approach Rate, Overall Difficulty and HP Drain Rate, while decreasing circle size and adding an extra 6% to the score.[5]
  • Sudden Death and Perfect (commonly abbreviated as SD and PF, respectively) cause player to fail the map if combo is ever broken by missing a hit circle, slider tick, or failing to complete a spinner, but will not be broken by missing a slider end. Perfect mode causes player to fail the map if accuracy ever decreases under 100%.[6]
  • Double Time and Nightcore (commonly abbreviated as DT and NC, respectively) increase the BPM to 150% of its original value and decrease duration of the song by 33%. Nightcore also increases pitch of the song. In original and Taiko gamemode, this mod adds extra 12% to the score. In Catch the Beat gamemode, 6% is added to the score.[7]
  • Hidden (commonly abbreviated as HD) causes absence of the approach circle and the hit circles vanish immediately after showing up. Sliders vanish over time as player continues to follow the slider track with their cursor. The player has to click on the correct position of the note at the correct time to score a hit. In Taiko, Catch the Beat and osu!mania, notes disappear about halfway through the screen. Like Hard Rock, this adds 6% to the score.[8]
  • Fade In (available only in osu!mania) is an inversement of Hidden in osu!mania, making the notes fade in as they reach half of the screen. This mod doesn't add any score bonus, since it is unique to osu!mania gamemode.[9]
  • Flashlight (commonly abbreviated as FL) causes the screen to go black, except for a small area around the cursor. When combo multiplier reaches 100 and 200, the field of view shrinks to a smaller area, returning to its original state if the combo is broken. This mode adds 12% to the player's score.[10]


These mods are the mods that don't apply to other categories. These mods make the play "unranked" and scores not being kept (excluding "1K"-"9K", "Co-op" and "SpunOut" mods).

  • Relax (unavailable in osu!mania) allows the player to only move the cursor, while the notes are hit with perfect timing automatically. It is impossible to fail in this mode. In Catch the Beat gamemode, this mode allows the player to use their mouse to control the character.[11]
  • Auto Pilot (osu! standard only) makes it so that the player only needs to click and cannot fail.[12]
  • Spun Out (osu! standard only) makes the game to automatically complete spinners for you.[13]
  • Auto allows the player to watch a perfect play of the beatmap (with some exceptions).[14]
  • Cinema shows only background and storyboard, while automatically playing hitsounds on time. It is possible to use Double Time, Nightcore and Half Time alongside this mod. Background dim will be set to 0%, and background video and storyboard will be tuned on, while this mod is in effect.[15]
  • xK (osu!mania only) will force all osu!mania beatmaps to use the selected key setting, ignoring the original key setting of the beatmaps. It is possible to choose key settings from 1K to 9K. This mod reduces the score by 33-10%, depending on selected key setting. If selected key setting matches the original, score is not changed.[16]
  • Co-op (osu!mania only) introduces a second playfield with second set of controls based on current key count (e.g. 7K -> 7K + 7K). For osu!mania specific maps, the key count is split in half, while on maps with odd key count, one set of controls has an extra key (e.g. 5K -> 2K + 3K). It is possible to increase the key count to 18K by combining Co-op and 9K mods. Note that this is possible on beatmaps, which are not osu!mania only.[17]
  • Random (osu!mania only) causes the note placement to change, while it does not affect the note timeline.[18]


These mods does not appear on "Stable" build. Due to their experimental nature, please proceed at your own risk. Also, the current name is probably a placeholder name. It might change.

  • Target Practice turns the game into a game as described by the title, and the speed is determined using the "BPM".

Mods with opposite effects cannot be used at the same time (e.g. Hard Rock and Easy cannot be used simultaneously). If multiple mods are used together, the final score multiplier would be the result of the multipliers carried by each mod multiplied together(e.g. if a Hidden mod along with an Easy mod was used simultaneously, the final multiplier would be 0.50 x 1.06 = 0.53).

Other game modes[edit]

osu! features three special game modes that are accessible in the mode selection of the play menu: Taiko, Catch the Beat, and osu!mania. These game modes allow a different style of gameplay from the standard play mode.


The Taiko mode is based on Taiko no Tatsujin, another rhythm game which involves hitting drums to the beat of a music piece. Taiko mode does not require the use of the cursor except for browsing the beatmap list and the pause menu. Instead, only clicking is required, which is done on a keyboard. However, the osu! community has found various ways of supporting a Tatakon or DrumCon controller intended for the Taiko no Tatsujin PS2 games. Usually, an external script is used to map the controller input to keys on the keyboard. A PlayStation to USB Controller bridge is required to adapt the controller for a computer.

When playing the Taiko mode, red and blue beats, as well as long yellow drumrolls (with an appearance similar to a slider) will scroll across the screen – the player gets more points for the more hits they can achieve. In the original Taiko no Tatsujin games, the red beats are referred to as "dons" and the blue beats "kats". The red beats represent the Taiko (drum) center and the blue beats the rim. Spinners are also present in the Taiko mode. Towards the left of the screen is a stationary circle. A player must hit the key(s) corresponding to each coloured beat when a beat passes under this circle. Key configuration can be reviewed and changed in the Options menu, under Input.

To hit the red beats, players must hit one of the two Taiko inner hit buttons. For blue, a Taiko Outer hit button must be pressed. When a large beat passes under the circle, pressing both corresponding keys will earn players extra points. When a long beat passes under the circle, players should tap to the rhythm in order to earn points. When a spinner appears, they must alternate hitting the inner and outer hit buttons until the number at the bottom reaches 0.

Catch the Beat[edit]

This mode puts the player in control of a character (named Yuzu) holding a plate above their head, with the objective of catching fruits falling from the top of the screen.

Regular beats on a map are converted simply to fruit falling straight down. Sliders have one fruit at each end of the slider and a trail of juice drops leading between the ends. Large juice drops are the equivalent of slider ticks, while small drops add extra points to the score and affect accuracy. Spinners become fruit falling en masse from the top of the screen; the player does not need to catch all of the fruit, although catching more fruit will earn them more points.

Screenshot of "osu!mania."


Osu!mania is a mode similar to Beatmania IIDX and DJMax where players need to press keys bound to several columns according to the music. As the music plays, notes are falling from the top of the screen in several columns whose number depends on the map. As a note reaches the bottom row of some column, the player is expected to press the key bound to that column to clear the note.

A special set of mods is available in osu!mania, namely 1K, 2K, 3K, 4K, 5K, 6K, 7K, 8K, 9K, Co-op, Fade-In. Usually beatmaps are meant to be played by a certain amount of keys set for the beatmap; however, using one of these special mods (1K-9K) can change this amount of keys for a score reduction. In osu!mania, mods don't add any score bonus, since maximal score for any osu!mania beatmap is set to 1,000,000.

This mode was made public on September 30, 2012.


The game uses player designed "beatmaps", which are the files containing the actual gameplay data. These are created using an in-game editor, allowing the user to pick any song they like and produce beats for it. Beatmaps for specific songs can then be shared through an in-game uploader directly linked to the main site. Players can then provide feedback for the beatmaps, referred to as a "mod", usually suggesting some means of improving its quality. After the author has modified the beatmap according to the tips it received and the Beatmap Nominators are content with its quality, they may nominate it for ranking. Beatmaps must then undergo a seven-day trial period in the "qualified" beatmaps section, after which they will be moved to the "ranked" beatmaps section. Qualified maps have a high chance of returning to pending if an issue is found by a member of the Quality Assurance Team.[19] Statistics for each ranked beatmap are maintained on the osu! website. Scores for each ranked beatmap are totaled to determine a player's ranked score, which determines a player's score ranking.

As of April 13, 2015, over 300,000 beatmaps have been created, out of which over 10,000 have attained ranked status. The number of ranked maps gradually increase as the Beatmap Nominators rank newly submitted maps.[20][21]


On June 3, 2008, multiplayer was added to the public release (b335).[22] Multiplayer consists of a central lobby displaying available rooms, and current online players. Rooms are created with the "New Game" button. A game begins when all players in the room are labeled as "Ready" and the host clicks start. The Multiplayer game is made up of the normal components as a Single Player osu! game, but with the in-game scoreboard displaying the current rankings of the players in the room. All play modes (including Taiko, Catch the Beat and osu!mania) are available in multiplayer mode, as well as a variety of scoring rules, such as osu! Standard Score, where the highest score wins, or osu! Standard Accuracy where hitting the notes perfectly seizes the top spot. Players are also able to play tag co-op where the room works as a team to complete the song as each player is given certain beat clusters to hit, 1 player at a time. As of release b593a, Tag Team mode has been introduced where players are sided on two teams (Red and Blue) and work as one to win.

Critical reception[edit]

The game has been featured in several magazines and websites.[23][24] The reception has generally been positive, with the biggest complaint being that playing osu! with the mouse takes a long time to get accustomed to.

Non-PC Platforms[edit]

As of November 2008, an iPhone/iPod Touch osu! port was announced and was released to the general public on January 2009 via Cydia repositories.[25]

An official App Store version of osu! entitled osu!stream was released on 08/01/2011.[26] osu!stream does not allow for user made beatmaps to be played, instead allowing only a select number of songs that are purchasable from an in-game store.

There is also an outdated port of osu! that has been released to Android known as osudroid!. It has been replaced by 3rd party ports such as opsu! or an unofficial patch for osudroid!

At the Malaysia Comic Fiesta 2013 in Kuala Lumpur, peppy released his new osu!tablet.[27]

A version of osu! for Windows Phone 7 and 8 devices called osu!WP has also been released.[28]


An official version in the Apple App Store was added for the iPhone/iPod Touch called osu!stream.[29] This version of the game does not include custom beatmaps. It instead has both free and paid beatmaps available for download in the ingame store.

On January 3, 2014 osu!stream was removed from the iOS App Store for copyright reasons.[30] However, it was re-added to the iOS App Store on January 28, the same year.[31] Since the copyright infringement letters, beatmaps with links to beatmania IIDX or Skrillex have been removed, although they can be found through external sources.[32][33]

osu!stream has three gameplay modes:[34]

  • Easy: Slow beats, and it is impossible to fail.
  • Stream: This mode is unique to osu!stream. This mode causes the gameplay to switch between "streams", or different difficulties in a single game based on the player's performance.
  • Expert: Can only be unlocked if the player has achieved the ranking of "A" or better in stream mode. In this mode, gameplay is difficult with beats appearing faster, more stacking beats, more connected beats and faster drain of the health bar.


The community includes over 7,650,000 registered users, with a total of over 4.00 billion ranked plays.[35]


osu! offers perks to players who contribute $4 or more. Supporters can download beatmaps directly on the osu! client, and can automatically download from spectator or multiplayer matches as well as several other perks.[36]

See also[edit]


  1. ^ http://www.windowsphone.com/en-us/store/app/osu-wp/83be2e91-48ca-4cfe-9a0d-851b01e62d42
  2. ^ https://osu.ppy.sh/wiki/Game_Modifiers#Easy
  3. ^ https://osu.ppy.sh/wiki/Game_Modifiers#No_Fail
  4. ^ https://osu.ppy.sh/wiki/Game_Modifiers#Half_Time
  5. ^ https://osu.ppy.sh/wiki/Game_Modifiers#Hard_Rock
  6. ^ https://osu.ppy.sh/wiki/Game_Modifiers#Sudden_Death
  7. ^ https://osu.ppy.sh/wiki/Game_Modifiers#Double_Time
  8. ^ https://osu.ppy.sh/wiki/Game_Modifiers#Hidden
  9. ^ https://osu.ppy.sh/wiki/Game_Modifiers#Fade_In
  10. ^ https://osu.ppy.sh/wiki/Game_Modifiers#Flashlight
  11. ^ https://osu.ppy.sh/wiki/Game_Modifiers#Relax
  12. ^ https://osu.ppy.sh/wiki/Game_Modifiers#Auto_Pilot
  13. ^ https://osu.ppy.sh/wiki/Game_Modifiers#Spun_Out
  14. ^ https://osu.ppy.sh/wiki/Game_Modifiers#Auto
  15. ^ https://osu.ppy.sh/wiki/Game_Modifiers#Cinema
  16. ^ https://osu.ppy.sh/wiki/Game_Modifiers#xK
  17. ^ https://osu.ppy.sh/wiki/Game_Modifiers#Co-Op
  18. ^ https://osu.ppy.sh/wiki/Game_Modifiers#Random
  19. ^ "Beatmap Listing". Retrieved 2015-04-13. 
  20. ^ "Beatmap Listing". Retrieved 2015-04-13. 
  21. ^ "Beatmap Listing". Retrieved 2015-04-13. 
  22. ^ "osu! Public Release b335". Retrieved 2014-09-10. 
  23. ^ "Free PC Ouendan/EBA emulator hits public beta". Retrieved 2014-09-10. 
  24. ^ "Osu! - Download". Retrieved 2014-09-10. 
  25. ^ "osu! for iPhone and iPod Touch". Retrieved 2014-09-10. 
  26. ^ "osu!stream on the App Store on iTunes". Retrieved 2014-09-10. 
  27. ^ "osu! panel at Comic Fiesta 2013 - YouTube". Retrieved 2014-09-10. 
  28. ^ "osu! WP". Retrieved 2014-09-10. 
  29. ^ "osu!stream". Retrieved 2014-09-10. 
  30. ^ "ppy - Apple IP infringement policy woes (aka where is osu!stream?!)". Retrieved 2014-09-10. 
  31. ^ "osu!stream on Twitter: "osu!stream is once again available on the app store! hoping to submit a new update over the coming week some new stuff :)."". Retrieved 2014-09-10. 
  32. ^ "Removal Request on Konami's Contents (Bemani Series)". Retrieved 2014-09-10. 
  33. ^ "DMCA Notice (Skrillez / GrayZone)". Retrieved 2014-09-10. 
  34. ^ http://osu.ppy.sh/wiki/Osu!stream#New_Modes_to_replace_the_difficulty difficulty levels of osu! stream. Retrieved March 2, 2013
  35. ^ "osu!". Retrieved 2015-11-26. 
  36. ^ "Supporting osu!". Retrieved 2014-08-17. 

External links[edit]