Z-canceling is when you shield (press Z) before hitting the ground while doing an aerial, and the landing lag from the aerial completely disappears. The timing differs from move to move, but the effect remains the same.
the easy way: spam z button every time you are about to land since z button in the air does nothing. the right way: every time you attack about to land, press z, when done right, you should not see shield coming up and you can move right away.
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