Taiko is a special game mode in osu! that borrows almost all of it's elements from the Japanese rhythm game, Taiko no Tatsujin (Released as Taiko: Drum Master in North America).
In this game mode, players hit the drum (or keyboard) in time with blue or red notes on the screen. Red notes indicate that you must hit the middle of the drum (x or c on keyboard controls) and blue notes indicate that you must hit the rims of the drum (z or v on keyboard controls). Large red or blue notes indicate that you have to hit both sides of the drum, middle or rim according to the color of the notes. Long yellow notes indicate a roll of either red or blue notes. These do not add to your combo or cause a combo break if you choose not to roll throughout the entire thing. However, different from Taiko no Tatsujin, there are upper limits of hits on the slider which is 4 times of the length of slider while it is 8 times of the length of the slider in songs that is equal or lower than BPM 125. If sliders were hit too fast, no hit is recorded during slider.
In the osu! variant of Taiko, red balloons and bells found in some versions of the console game have been removed and replaced with a shaker that mimic's the osu! spinner. This shaker requires the player to alternate between rim and middle to whittle down the number on the screen before the next set of notes appears. Unlike some other rhythm games, players can play random notes to the beat without fearing a point deduction, as long as other notes are not on the track.
Currently taiko-only mapping is available in the edit mode, while a beatmap is rankable with taiko-only difficulties. Red notes refers to no hitsound Hit Object, while blue notes need a whistle or a clap on a hit circle. Large red notes need a finish, while large blue notes need both finish and whistle together). Slider represents long yellow note (also known as drumroll) and spinner represents shaker. When mapping taikosu! or authentic maps, note that short sliders (usually less than a beat) are converted into ordinary circles in Taiko mode unless the map is set to Taiko-only. For maps with BPM125 or lower, 1/8 drumroll are given instead of 1/4 drumrolls. As 1/8 rhythms may not appear in the music, it's not suggested to place slider in this case. Note that 1/6 drumrolls is given if slider tick rate 3 is used.
In a full-combo attempt, since GOOD always counts as 50% unlike in osu!'s main game mode, you can easily tell whether you're going to get a S, A or B just by looking at the accuracy counter:
* S - 95% above (90+% GREATs, or less than 1 GOOD for every 10 notes) * A - 90% above (80+% GREATs, or less than 1 GOOD for every 5 notes) * B - 85% above (70+% GREATs, or less than 1 GOOD for every 3.33 notes)
Each GREAT is worth 300 + RoundDown(Combo / 10) times n up to a maximum of 300+10n points in which n depends on the difficulty rating of the song. A typical value of n (4.5-5 star difficulties) is 80, which gives a maximum score of 1100 at later combos. For 4-4.5 star difficulties, n is equal to 64 in which the maximum score per hit is 940. In the hardest case n is equal to 96 in which the maximum score per hit is 1260. Yet there are lower value of n for even easier difficulties.
Each GOOD gives half of the score as GREAT does, while zero score is given for MISS/BADs. Double score is given for successful hit large notes (different from Taiko no Tatsujin, left and right drum must be hit at the same time very precisely in order to allow a successful hit of large notes). For yellow long notes, 300 is given per hit in the small one while 600 per hit is given to the large one. For shaker notes, each shake gives 300 and finishing the shaker gives score twice as much as a GREAT of the current combo.
Unlike osu! or CatchTheBeat, a miss in Taiko will not reduce the score from maximum possible score greatly. Instead, constant score is reduced per miss if each miss is separated by more than 100 combos. (With the existence of shaker and large notes, score loss would be larger) For example, in typical difficulty, breaking a combo in the middle of a song without accounting for large notes and spinners, would result in a maximum loss of 44,000 points (to bring the combo back up to 100).
Also unlike the other game modes, Kiai Time has an effect on scores. While Kiai Time is active, the drum in the upper left changes animation, the playfield has a background gradient and the hit area gains a fire graphic around it. Additionally, all hit notes gain a 1.2x score multiplier, long yellow notes included, except for hits on a shaker (the final hit is still multiplied.)