Rocket Start

"Be patient, drivers! If you tap the screen too early, you'll fail the Rocket Start and be at a disadvantage."

- Lakitu

A Rocket Start (also referred to as a Rocket Boost, Turbo Start, Boost Start, or Head Start) is a technique used in the Mario Kart series as well as the racing games of the Donkey Kong franchise, such as Diddy Kong Racing. It is a powerful burst of speed that occurs at the beginning of every race, and it easily accelerates racers to top speed from standing still. It is executed by holding the acceleration button at the correct time in the starting countdown, with each game having different timing to do so, although the general timing of the technique in most games is to press the button sometime when the number 2 or equivalent appears onscreen. If the player holds the button too early and over-revs when the final beep sounds, the player's vehicle will backfire and stall for a few seconds at the beginning of the course (sometimes known as a Dud Start or Fail Start).

Strength
Since Mario Kart DS, the strength of the Rocket Start depends on the power of the rev at the moment before START/GO! appears onscreen. For example, if the player starts to rev the engine when the countdown reaches 2, depending on when the player started to hold down the acceleration button when 2 was onscreen, the duration of the technique can be roughly between 0.5 and two seconds, indicated by the flames coming out of the exhaust pipes of the vehicle (ink when the player drives the Inkstriker or Splat Buggy, magic when the player drives Kamek's Zoom Broom or its variants, and soda when the player drives the Combo Cruiser). In other words, if the player starts to rev right at the moment the countdown reaches 2, the resulting rocket launch from the starting grid would be longer than if the player started to rev half a second after the 2 came onscreen. In Mario Kart Tour, in addition to the technique from previous games, releasing the tap when GO! appears onscreen (due to auto-accelerate permanently enabled) results in the Rocket Start being longer and awarding more points than usual, with the character's "item success" animation indicating a longer boost. A bonus challenge called Ready, Set, Rocket Start grades players on how many points earned for the Rocket Start, but it appeared only in the game's beta test, the New York Tour, the Tokyo Tour, and the 2020 New Year's Tour.

Mario Kart Tour stats
The following karts in Mario Kart Tour increase boosting time and points from Rocket Starts.

Controls
To perform a Rocket Start, drivers must press and hold the corresponding acceleration button when the race is about to begin. How and when to use it depends on which installment in the series and which control scheme the player uses.

Arcade series

 * Mario Kart Arcade GP – same as in Mario Kart: Super Circuit and Mario Kart: Double Dash!!
 * Mario Kart Arcade GP 2 and Mario Kart Arcade GP DX – pressing down on the accelerator when "1" appears on the screen

Double Dash
The Double Dash is a technique that can be performed only in the co-op play mode of Mario Kart: Double Dash!!, and it is named after the game's subtitle. Both players must press at the same time when the three red lights on Lakitu's starting signal turn green to perform this technique, which launches the kart at a higher speed. Blue flames follow the kart, showing that the technique was performed correctly.

Mario Kart 64

 * Instruction booklet: "When you start, if you press the Button when the signal changes from red to blue, you can make a dash start at maximum speed (called a "Rocket Start"). But if you press too early, the tires will spin and you will start even slower, so be careful."

Mario Kart: Super Circuit

 * Instruction booklet: "If you press the button at just the right moment before the light turns green, you'll start the race with a huge burst of speed."
 * Electronic manual: "When the race is starting, if you press on the accelerator after the second signal flashes--and with just the right timing--you will perform a Rocket Start and shoot off the starting line."

Mario Kart: Double Dash!!

 * Instruction booklet (Rocket Start): "If you press just as Lakitu's start signal turns green, you'll perform a Rocket Start."
 * Instruction booklet (Double Dash): "In co-op play you can get an even better launch if both the front and rear perform a Rocket Start at the same time. This is called a Double Dash."

Mario Kart DS

 * Instruction booklet: "During the countdown to the start, hold down with the right timing to rev up your engine and give yourself a burst of speed off the starting line."

Mario Kart Wii

 * Instruction booklet: "Press and hold at just the right time during the countdown to rev up your engine and give yourself a burst of speed off the starting line."

Mario Kart 7

 * Electronic manual: "If you press and hold or  at just the right time during the starting countdown, you will launch off the starting line much faster than normal."

Mario Kart 8

 * Electronic manual: "Get off to a Rocket Start! To launch from the starting grid at a high speed, press and hold at just the right moment during the countdown."
 * Guide: "Timing a perfect Rocket Start can determine the whole nature of a Grand Prix race's first lap, and this technique is essential for posting record-breaking Time Trials. When Lakitu begins the countdown, start accelerating when "2" is on screen and the second red light is lit. If this is well timed, you'll have a perfect Rocket Start."

Mario Kart 8 Deluxe

 * In-game manual: "Get off to a Rocket Start! To launch from the starting grid at a high speed, press and hold at just the right moment during the countdown."
 * Guide: "Timing a perfect Rocket Start can determine the whole nature of a Grand Prix race’s first lap, and this technique is essential for posting record-breaking Time Trials. Pay attention to Lakitu’s countdown, and begin accelerating immediately after the “2” appears onscreen, accompanied by a tone. Properly done, you’ll rocket off the line with a Mushroom-like boost. If you begin accelerating too soon, as the tone sounds and the 2 appears, rather than just after, you’ll stall at the starting line."

Mario Kart Tour

 * Tips & Tricks: "At the race's start, tap the screen and hold on 2, then release at GO to take off with a Rocket Start! The closer you are to GO when you release, the longer your dash will last and the more bonus points you'll get. But be careful... You'll stall if you tap too early!"
 * FYI! (From Ready, Set, Rocket Start): "Tap and hold the screen when the countdown reaches 2, release at GO for a Rocket Start!"

Nintendo Extra

 * "At the start of a race, hold the accelerator button when the countdown reaches “2” to perform a Rocket Start! Get the timing right and you’ll zoom off the start line much faster than usual!"

Trivia

 * In Paper Mario: Color Splash, the Rocket Start is used by Luigi in his Standard Kart before he transports Mario and Huey up the rainbow to Black Bowser's Castle near the end of the game. It uses Mario Kart 8's chimes.
 * The opening of The Super Mario Bros. Movie shows from the  series revving up the kart engine at the starting line before backfiring as the Illumination logo lights up, just like in the Mario Kart series.