Look at any fight of Kakashi's, he fights with both eyes open.
Originally Posted by Koo
Like I said, google image search ''Hatake Kakashi'' and you'll see TONS of images of him fighting with both eyes.
You know what, I'll do it myself...Hold on...
This is during his fight with Itachi, clearly using BOTH eyes.
Here, during the Zabuza fight on Naruto bridge, you can CLEARLY see Kakashi using his Raikiri accurately with BOTH eyes open.
[EDIT] let me rephrase that, during the moment of which Kakashi strikes with his Raikiri, he closes his normal eye.
BUT, during this fight with Pein, he's had his eye closed THE ENTIRE TIME, regardless of weather he was doing Raikiri or not.
Yet again, we see Kakashi fight Itachi with both eyes open, and this time, at about 5:00, Kakashi strikes with his Raikiri with BOTH eyes open.
He strikes accurately, but Itachi's speed is no match for it.