When your opponent is up in the air (off of the ground), you can walk forward and pass underneath them so that you are on their other side when they land.
They need to be high enough up that their feet are above your character’s head during this time so that you can actually make it through. If they are too low you will just walk into them.
They could be in the air because they jumped, but there are also other situations that will put someone in the air. For example: when an opponent escapes from Boxer’s throw, they will flip backwards and be in the air for a moment. At this moment, you can walk under them.
[media=youtube]s7ebxFD1O90&#t=2m38s"[/media] cross under off of the RH hold.
[media=youtube]yY3Yx9mT6Ks"[/media] is loaded with unusual ways of crossing up opponents without having to jump.
0:42 Ken uses crazy kicks to pass through Ryu.
0:48 Dictator does a slide while Guile is airborne and when Guile lands he’s crossed up.
1:05 Honda does a hold against a cornered opponent then walks under them and does a cross up sweep.
1:14 Dictator passes right through Claw due to inertia and wacky hitbox properties.
1:20 Blanka hops through Ryu and gets a dragon punch to come out on the wrong side.
2:11 Dictator does another cross up slide.
2:28 Sim does a cross up slide underneath Chun.
2:44 Cammy anti-airs Fei then walks underneath him for a cross up.
2:53 Dictator crosses through Zangief using a corner trick (more on that [media=youtube]sKVjpAGnMTQ"[/media]).
2:57 Chun ends up on the opposite side after a corner throw.
3:14 Ken walks under his opponent after a kneebash (Damdai used this in HDR at EVO last year).
3:18 Blanka rolls through his opponent and ends up on the opposite side.
