itachi's true gift to naruto....
if you really wanna know itachi's gift to naruto here it is, kishi,. has been using japanese mythology all through the manga
1. sword "Totsuka" no Tsurugi : was the sword that trapped orochimaru
2. mirror "Yata" no kagami : was the shiled that itachi used against sasuke thunder god attack
3. jewel "Yasakani" no Magatama : this is the only artifact of the three legendary artifact from japanese mythology, that has not made an apperance on the manga, and if you look at it its a jewel that looks like a comma, identical to the simbols, on naruto stomach, and neck, that appear on his body when he goes kyuubi mode, so I'm guessing that the kuubies chakra has some kind of reaction to itachi's gift and that's why those symbols, appear......
fior more info you could read more on this from dragon-lord's theory, wich really is truth, there is no doubt in my mind, with what has happen so far in the manga
this is the link to dragon-lord theory " Itachi's gift to itachi "