This isn't about phasing a ten-mile long and two-mile wide bullet of alien metal. That's actually simple enough. I mean, this IS a comic book.

   No...I mean when did she gain the ability to phase without having to breath.  She couldn't phase through that much metal - or for that matter, that much of anything solid - on a single breath. I'm going to suggest that she may have learned to sift breathable oxygen from matter as she passes through it. But...is this an ability she had before Joss wrote her?

   Also, she'd aparently learned a REALLY coot trick where she could keep herself in phase while unphasing one part of her (punching Emma in the face while the rest of her body was still phased), and I have no problem with that. I mean, powers evolve. I can easily imagine her learning how to do this sort of stuff.

   But does anyone know WHEN she learned it? Or, was it just all Joss? Did Joss evolve her powers, or did he just not understand them?

Was she breathing while phasing?  I have to admit, I don't remember it.  I know she travelled long distances underground, but I thought she still had to come up for air... ??

I like your attention to detail! I'm gonna assume Joss took artistic liberties seeing as how I don't recall any reference to the expansion of her abilities in dialouge or narrative.

I.E. He didn't care how they worked exactly.

I never looked at her powers that way. Huh.

She's always been able to phase partially, but she's never been able to breathe while phasing.
Though now that i think about it how did she survive when she was stuck in phase after the Morlock Massacre?

She can breathe while phasing just not while phased in a solid object in cases such as that she has to hold her breth

In the uncannyxmen.net  bio. kitty does not have to hold her breathe, her powers are ephemeral  which is like a eleco magnetic repulsion force field that allow her to pass through solid objects.

If she is phased...air would pass through her....so by the very act of phasing you don't have to breath.

"Was she breathing while phasing?  I have to admit, I don't remember it.  I know she travelled long distances underground, but I thought she still had to come up for air... ?? "

Well, Ogun transfered all of his fighting knowledge into her when she was possessed and all signs point to her not losing that information. This newer stuff isn't exactly newer to Kitty anyway. If you thought her Emma fight was impressive, check out her fight with Wolverine ("Death"). She was beating the crap out of him with duel Katana. He only won because he outsmarted her by stabbing her solid foot.

"   Also, she'd aparently learned a REALLY coot trick where she could keep herself in phase while unphasing one part of her (punching Emma in the face while the rest of her body was still phased), and I have no problem with that. I mean, powers evolve. I can easily imagine her learning how to do this sort of stuff."

What is current Kitty's abilities

@03S7: current kitty is a badass h2h fighter and can even time bullets with eass, so she's up there with characters like psylocke in h2h.

as for her phasing powers, the best I've seen from her was her phasing a skyscraper X men gold #1.

@dami24434: damn alright so she probably couldn't hang with Kenshiro