Superman. What's a kakashi? Isnt that some kind of cereal.
Kakashi Go Lean or something. Kidding. But seriously, what's a kakashi?

All superman has to do is grab him, fly into space, throw him back to earth and watch him burn up on re-entry.

Suggestion for next poll:

Chuck Norris vs every anime character ever

I don't see how Kakashi could possibly find out his weakness by fighting with him like he would another ninja. Superman's weakness isn't some lapse in technique, it's a rare foriegn element that Kakashi wouldn't have a hope in hell of finding, or even knowing about.

Depends on what era Superman we're talking about, I think. If it was OMFG Golden Age Superman, he has every power ever and absolutely no weaknesses, including the ability to write his own stories. He'd retcon Kakashi into nonexistence.

Kakashi, meanwhile, has the ability to turn day into night, being a ninja and all (how else could they be so successful?). He should have no trouble making the sun into a red star.

Kakashi: "Hey look, my eye turns into a super kawaii design. Ah-ha! Now your trapped."

Superman: "Say Mxyzptlk 3 times."

Kakashi: "Mxyzptlk, Mxyzptlk, Mxyzptlk...why?"

*stupid trap dimension disintegrates*

Superman: "Now let me show you what my eyes can do."

I doubt Kakashi has kryptonite kunai so..... Superman could pretty much rip Kakashi's chest cavity open and clench the still beating heart between his teeth.

O_o Kakashi would just be too smart to get caught in such a hopeless situation.

Kakashi