Glacius shows the difference in timing between HP auto-doubles and HP manuals. Both combos press the same buttons but with different timing; manuals must wait for the linker to fully recover.
You may have noticed that every combo mechanic that’s been discussed so far has been a cancel. Auto-doubles are canceled from linkers, while linkers are canceled from auto-doubles, and openers can be canceled into both. Modern Street Fighter games, meanwhile, consist of combos that are largely about linksTwo moves will link together if you are able to fully recover after executing one move and still connect another move before your opponent leaves hitstun. Cancels will remove the recovery of the first move and transition seamlessly into the second move, whereas links require you to wait until the first move is fully complete.. Killer Instinct’s combo engine repurposes links through the concept of manuals.

Manuals are simply a normal attack executed with link timing, virtually always after an opener or a linker. Barring some character-specific exceptions typically saved for combo video fare, manuals can replace auto-doubles in the combo sequence; any time you do an auto-double, you could have chosen to do a manual instead, and manuals are cancelable into linkers just like auto-doubles. Unlike auto-doubles, you do not get a two-hit version of your normal. Instead, you will get the version that your character would normally perform in the neutral game. Apart from two-hit command normals, this means manuals are distinguished from auto-doubles because manuals hit only once, and they will appear very delayed. Advanced players will mix and match auto-doubles and manuals throughout a long combo to keep the opponent guessing.

It's very crucial to note that the existence of manuals does not fundamentally change the combo system as it's been described so far. The thought of constantly performing normals into specials and back again is very much unchanged; manuals simply give you a choice to perform a 2-hit normal by pressing the button early, or a 1-hit normal by pressing the button late with good timing. You must still alternate between normals (auto-doubles or manuals, your choice) and specials (linkers) to perform combos in KI, so it's best to think of this addition as a very small wrinkle in the strategy, rather than an overhaul of the system.

A closer look at the timing required for Glacius's HP manual after Heavy Cold Shoulder linker. You must wait until the end of the linker to attempt a manual, and the window is much smaller than an auto-double.
Because manuals are links and not cancels, you must wait for the entirety of your opener or linker to complete before you press your normal button, and they require precise timing. If you press your button too early, you’ll get an auto-double, and if you press it too late, your opponent will recover in time and be able to block. Some manuals are tight enough to be 1-frame linksThe tightest possible timing for a link. The manual must be input in the span of one game frame (1/60th of a second), or else the move will not connect., while others are significantly looser.

An important thing to realize is that Killer Instinct places restrictions on manuals after linkers. If you execute a linker of a particular strength, you will only be able to follow it up with a manual of the same strength or lower. This means that light linkers only can be followed by LP or LK manuals, while heavy linkers can be followed by any manual. This is an interesting risk/reward balance which forces offense to go for an easier-to-break heavy linker to get access to the full suite of manual options. Attempting the strongest possible manual allowed after a linker is usually pretty tight; light linker into light manual is often a 1-frame link, while heavy linker into heavy manual is usually no harder than a 2-frame link. Meanwhile, attempting a lower strength manual is usually quite easy; heavy linker into light manual can have a 6-frame window or more. Manuals after shadow linkers are not restricted, and slow heavy manuals are usually possible after openers, although this is character dependent.

Jago performs a combo that mixes auto-doubles and manuals, including manuals after an opener and a shadow linker. Can you identify the pieces?
(show combo)
Light Laser Sword opener (1 hit)
Crouching LP manual (1 hit)
Light Laser Sword linker (1 hit)
HK auto-double (2 hits)
Heavy Wind Kick linker (3 hits)
Close MK manual (1 hit)
Medium Laser Sword linker (2 hits)
Shadow Wind Kick linker (5 hits)
Close HP manual (1 hit)
Tiger Fury Ender (Level 4 = 4 hits)
Fulgore demonstrates the manual restriction rules.

The inner workings of the manual system are, of course, based on frame dataFrame data exposes the inner workings of every move in the game. It will measure how many frames a move has on startup and recovery, as well as how advantaged you are if your move hits or is blocked. Moves that leave you heavily advantaged on hit are prime candidates for manual follow-ups. KI's training mode shows you the frame data for every move.. Most Killer Instinct special moves are not massively advantaged on hit (most in the +1 to +3 range) but many close normals in the game have high startup. To allow links to be possible, Killer Instinct has a special move-dependent buffer window which allows a normal attack to execute slightly before the linker fully recovers; for most linkers, experimentation has shown this window to be about 5 frames, although some linkers adjust this window slightly in order to better enforce the manual limitation system. This means if a linker leaves you at +4 on hit, a 9-frame normal can be performed as a manual by pressing the normal 5 frames before the linker finishes. Fortunately, you don’t need to memorize a bunch of frame data to perform manuals in Killer Instinct. Simply remembering the manual restriction rule is enough; light linkers lead to light manuals, medium linkers lead to medium or light manuals, and heavy linkers lead to all three manuals. The frame data has been carefully constructed to make these rules always true.

Comparing Auto-Doubles & Manuals

Since manuals can take the place of auto-doubles, it’s important to understand when and why you might choose to use each.

  • Auto-doubles do more damage: Because an auto-double is two hits while a manual is most often one, auto-doubles will do more damage. If your opponent is locked out from a missed combo breaker, you should never be using manuals to perform a max damage combo. Auto-doubles also do more white damage, which means they raise the ender level faster, but they also raise the KV meter faster.
  • Manuals are considerably more difficult to combo break: This is the main benefit that manuals provide; if combo breakers did not exist, manuals would not serve much purpose. This will be covered a bit more in-depth in the Combo Breakers section, but the window for breaking a manual is much less than an auto-double, and you are given much less of a visual cue. The window is small enough that breaking a manual requires a guess, instead of a reaction.
  • Manuals require more difficult execution: The window for inputting manuals is considerably shorter than any auto-double window, so bringing manuals into your game will require some practice. Whether the benefits are worth it depends on your interest level; it’s entirely possible to fully enjoy and compete at an interemdiate level in Killer Instinct without ever performing a manual (that is, they are not nearly as fundamentally important as links in a game like Street Fighter V), but you will not beat the world’s best players without some of the variation manuals provide.
  • Switching often between manuals and auto-doubles will throw off your opponent’s timing: Manuals must occur right at the end of your linker, but auto-doubles will cancel the recovery of your linker, which means being unpredictable with how you use auto-doubles and manuals will require your opponent to constantly switch when he looks to combo break. If he is expecting a manual but you do an auto-double instead, he may become confused at the varying pace of your combo and miss an opportunity.
  • Manuals have restrictions: Because breaking manuals is so difficult, the strength of manual you can perform is directly related to the linker that preceded it, which can lead to some predictable offense at times. These restrictions can be mitigated by switching between manuals and auto-doubles (which have no such restrictions), as described in the previous point, or by performing surprise resets when the opponent is looking for an “obvious” manual, but it is nonetheless a weakness of manual-only offense.

Good players will understand the strengths and weaknesses of both auto-doubles and manuals and use both regularly to keep their offense unpredictable and strong.

It's not a fighting game without exceptions.

Combo Traits