How do you do crossovers?

I hear people talking about them all the time, and I’m sure they’d be more effective in a game like Street Fighter in which you must hold back to block, but how do you do them? In MK9, once you jump over your opponent, your character immediately flips directions, but in SF, your character doesn’t flip directions until they land. So what am I missing here? Thanks.

jump over enemy and use attack that hits behind u

You need to use a move that has a hitbox sized and positioned well enough to hit the back of the opponent once you’ve passed their center. Ideally, the hitbox of your own move should be positioned at the bottom of your character, near your center (it should preferably cover your mid-point). This is because a character’s hurtbox (the part that you can connect with) usually spans their own center, and hitting them “behind” the center is what causes a cross-up.

eg. Zangief’s body splash is has very good cross-up ability:

Notice how large the hit-box (the red box is and how it’s spread around his center (the small yellow box below his character)

Compare this to Balrog’s jumping hard punch which has zero cross-up ability:

Though it’s not typically used as a cross-up, Ryu’s jumping hard kick has a hit-box that is close enough to the center to allow it to cross-up in some situations:

Ken’s jumping hard kick how ever will rarely, if ever, cross-up as the hitbox is situated further away from his own center:

I see, thanks! They’re pretty hard to land, though o_o

Not really, characters have moves that are great for crossing up depending on character.
I can only think of Hakan not having any crossup attack, maybe Balrog? and i could be wrong about that.

Gouken’s j.MK is really easy to crossup with.
I might be going out on a limb here but i think the general air kick to use is usually MK.

PS: You want a REALLY easy crossover kick, try Gen’s {Crane} j.MK!
His {Mantis} MK is also good.

I think it’s just something you’ll have to get used to, since Mortal Kombat makes you wait until your on the other side of them before attacking, otherwise you wont turn around.
Whereas Street Fighter you can attack as your jumping over them.

They are really easy to land, you just need to use the right jump attack. Which character are you trying it with?

Ibuki. I heard that her LP is best for crossovers, I must’ve heard wrong LOL

I don’t know much about Ibuki but I think her jumping mk is the one that crosses up. I could definitely be wrong about that though. I’m sure some Ibuki will chime in.

If you’re going to use a light attack to cross up, wouldn’t it be highly advisable to make sure it’s as deep as possible? Otherwise you run a risk of leaving yourself at a huge disadvantage due to the short block/hitstun recovery. Using mediums or heavy attacks have heavier hit/block stuns and will leave you slightly safer than a light.

The correct term is crossup. The word crossover usually refers to terms in games such as MvC3 (Crossover Counter, Crossover Combination, etc.)

Actually, Crossover makes more sense. Cross over…like…jump over…get it?

It depends what you are going for. Sometimes you want to be at a disadvantage eg. for an immediate tick throw or command grab. Lights also allow for ambiguous x-ups (hits at the back, lands in front).

dans got the best cross up, its hp hk at the same time in mid air.

is it even worth trying to cross up in mk, since theres a block button

It can mess up their inputs on wakeup moves since there is no autocorrect in that game.

yeah, this especially. But it’s also a good means to start a mix up / block string because an angled jump punch gives you lots of frame advantage