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Understanding Auto-cancels and IASA concerning Up-air/Bair


Smash Master
May 6, 2012
My friend was confused about Auto-cancels and IASA, so I decided I'd make a thread to describe them: and as such I picked the character I feel relates to them the most. I'm sure there has been threads before detailing these things, so I'm going to focus on a specific situation to show the aspects of each after I explain them.

*Note, these examples may be exaggerated and not may not be ideal for all similar situations: but they are for you to get the concepts.

First here's DK's Up-air/Bair frame data from Melee (which should be identical to P:M's)

AttackAirB | Back-Air

Total: 39
Hit: 7-15
IASA: 32
Auto-cancel: <6 20>
Landlag: 15
L-Canceled: 7

AttackAirHi | Up-Air

Total: 44
Hit: 6-8
IASA: 38
Auto-cancel: <5 13>
Landlag: 25
L-Canceled: 12
So let's look at Bair: we see that the move "ends" at frame 39. But it has IASA starting on frame 32, and Auto-cancels either before frame 6 or beyond frame 20.

IASA means Interruptable As Soon As, meaning you can do ANY action on or past the frame that IASA becomes avaliable and it will CANCEL the rest of the animation and do the move that you inputted. So If you inputted a jump on frame 34 it would cancel the animation through IASA and perform the double jump.

Auto-cancel means instead of going into the aerial's landing lag when you touch the ground (an amount of 7 frames given you L-cancel) you go into normal landing (Most characters normal landing is only 4 frames but for DK's it is 5 frames [at least in Melee]): which means it is the normal landing you would get if you did no Aerial at all and just landed from a jump. Usually the Auto-cancel frames are before the hit of the aerial comes out and a few frames or more after the hit frames have ended. So if you land with Bair on frame 5 you will go into normal landing, as well if you land on frame 22; but if you land on frame 19 you will go into the aerial's landing lag of 15 frames (7 with L-cancel).

Now here's the example of why this is important:

Different moves for certain characters have varying amounts of IASA and Auto-cancel timings, Donkey Kong's Bair and Up-air demonstrate this well. His Bair has IASA frames earlier than his Up-air (32 vs 38) but Auto-cancels much later (20 vs 13). This means that after performing a SH bair you can waveland out of it because of the early IASA, where with Up-air you cannot. But Up-air with its shorter Auto-cancel means Up-air can be Fastfalled sooner from a SH and still Auto-cancel where with Bair if you Fastfalled it as early as possible from a SH you would not land after the Auto-cancel frames had become active and instead go into the Aerial's landing lag.

So now with pictures I'm going to describe a situation where Sheik has been hit by either a Bair or Up-air: and based on Bair's shorter IASA than Up-airs, makes DJ to Bair(or any Aerial you think will hit) to hit Sheik again better than landing on the platform to jump and Bair, where with Up-air it is the opposite because the IASA comes so late in the move that Sheik will be out of hitstun by the time you are able to reach the IASA frame to Double Jump: so landing on the platform to Auto-cancel and then jumping off the platform into an Aerial is the better option.

Situation: You just hit Sheik with a Full hop to Up-air and she is flying away in Histun. Your full hop has made you close to a platform.

Do you wait for the IASA frames to come so you can DJ out and hit her with another Aerial(or just input another Aerial)? No, the IASA frames come too late. Instead land on the platform because of the Auto-cancel frames now being active, then proceed to jump and hit her with another Aerial

So Land (auto-cancel the Up-air)

Now Jump and do another Aerial (I just put another Up-air image as an example of an Aerial). Awesome. Note: Another advantage to this is you now have your Double jump where you would not if you had used it after the Up-air to perform the next Aerial, leaving you to possibly extend the combo even longer.

Situation: You just hit Sheik with a Fullhop to Bair. You are near a platform.

You are really close to a platform, should you land and Auto-cancel on it and then jump again and perform an Aerial to hit her? No, Bair has early IASA meaning you can Double Jump out of the move VERY early: you would be wasting 5 frames on the normal landing and more frames to jump back up (5 frames for his jump start) and then all those frames to gain height again.

Instead use the IASA to Double jump and do another Aerial on her (I just used Bair again as an example). Awesome.

More information on auto-cancels specific to characters:

-Normal landing is usually 4 frames for most characters but DK's and Ganon's is 5, Bowser's is like 6, and Pichu's is 2 [This not might be true for P:M].
-Jump start frames (how many frames the character just sits there after a jump is input before leaving the ground) varies from 4 frames (like Fox and 6 others) to 5 frames (CaptainFalcon and 7 others) and so on till 9 frames (Bowser)
-Also note in P:M IASA was also given the ability to Air dodge (from Brawl's mechanics), so while SH Bair WL for DK applies to P:M it does not in Melee (so you can do everything else like DJ/Aerial and all that but just not use the IASA to AD).
-More information about Normal landing/Jump starts can be found here: http://www.smashboards.com/showthread.php?t=30064

If people like this kind of teaching I might be able to make one similar for Luigi to describe utilizing frame differences of moves (like Nair) regarding combo breaking and other stuff



Another post with explanation: http://smashboards.com/threads/project-m-social-thread-v3-5.339825/page-1376#post-18240440
Last edited:


Smash Champion
Apr 27, 2006
Darien, IL
I don't even think this should be a DK specific thread. This is good to know for all characters.

Great work Mad.
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