PART ONE
I THINK I HAVE FIGURED OUT WHAT ITACHI'S GIFT TO NARUTO IS,you see,before even the sword of totsuka and the mirror of yata was shown in the manga,it was theorized by many that masashi kishimoto would bring these great treasures in the manga,but there are not two but THREE great treasures.
in the japanese mythology,there are "Six" Nobel Gods,Izanagi, Izanami ,Amaterasu,Susanno,Tsukuyoumi,and the insect looking God i call "zetsu"
Amaterasu Omikami, whose radiance shone through the "Six" directions (north, south, east, west, above, and below).I think this is where kishimoto got the idear of "the six paths"!!!!
In the ancient japanese mythology two gods descended from heaven, Izanagi no Mikoto and Izanami no Mikoto,these two high gods first created Amaterasu Omikami "the sun godess" and second they created Tsukuyomi no Mikoto "the moon god",and with the creation of the moon god,a terrible looking creature was born in the shape of a bug,the high gods were dissappointed in this and threw this insect creature or this "god" into the ocean,this creature is "zetsu",but his not called by that name there, I think later on he tries to kill tsukuyomi and become the moon god himself.
Anyway,After painful events, Izanagi, realizing that he had been polluted by his contact with death, decided to purify himself through bathing. Amaterasu Omikami emerged while he was washing his left eye, and Tsukiyomi no Mikoto while washing his right eye. A third deity, Susano-O no Mikoto, sprang from Izanagi�s cleansing of his nose during this ritual purification. These Three Noble Children thereupon received instructions from their August Parent, who directed Amaterasu to rule the day, Tsukiyomi the night, and Susano-O the ocean below,so this is why in order to activate susanno,mangekyou must be activated in both eyes,left and right!!!!,man,kishi stole everything from the japanese mythology,lol!!!!
and heres where itachis gift is revealed
once to save his sister,tsukuyoumi pierced an eight headed demon snake yamato no oroch with the totsuka which had sealing powers,and sealed yamato no oroch forever there,"kishi stole orochimaros idear from this"
Anyway,after an incident caused by susanno,Amaterasu ran away and hid herself in a cave,i think kishi stole this idear and created sasuke,lol,anyway,in order to bring her back to light,tsukuyoumi gave a sword "Totsuka" no Tsurugi and a mirror "Yata" no kagami and a jewel "Yasakani" no Magatama to Omoi-Kane no Kami,Omoi-Kane no Kami used the totsuka sword to battle demons on the journy,and when he arrived at the cave,he used the Jewel of Yasakani to shine a light and the yata mirror to reflect it,to show Amaterasu that there was still light in the world!!
so you see,the gift itachi gave to Naruto is simply the "Yasakani" no Magatama",and it will help naruto to show Sasuke that there is still some light in himself!!
-In the japanese mythology,The Jewel Of "Yasakani" is a symbol of "Benevolence" and has the Power To Shine A Light In The "Soul" and Stregthens the Soul,and it olso can light any kind of darkness
-The Sword Of "Totsuka" is a symbol of "Valor" and has the power to Pierce The Soul,and it olso can pierce and seal any being
-the Mirror Of Yata is a symbol of "Wisdom" - and has the power to Reflect The Soul,and it olso can reflect any attack.
Here is the photo of the three Treasure Weapons
https://www.uwec.edu/philrel/shimbut..._treasures.jpg
The Yasakani looks an awful lot like the Necklace that the sage of the six paths was wearing!!!!,and i bet the other two Treasure Weapons olso belonged to the sage of the six paths!!,and i suppose Itachi either stole them from Madara or he found them on his own!!!!,but ofcourse,the jewel is no use to itachi,but Naruto is the one who can use it!!!!
PART TWO
i think in naruto manga,these three items eatch belonged to the one of the three great eye clans
Byakugan - "Valor"
Sharingan - "Wisdom"
Rinnegan - "Benevolence"
Susanno and Tsukuyoumi were Amaterasu's brothers,Tsukuyoumi was a kind,loving and faithful brother to Amaterasu and Susanno was a horrible brother who killed every plant and tree in the forrest of Amaterasu,which was the reason Amaterasu ran away,so kishi stole this idear,and merged both susanno and tsukuyoumi and created itachi,in one side he is a kind,loving and faithful brother,and on the other side he is a horrible brother who killed Sasuke's clan.
Kami Tsukiyomi no Mikoto and Amaterasu were conceived as a pair because people thought of them as �eyes in the sky,� watching their actions at all times.So you see,kishi olso stole the moon eye plan idear from the japanese mythology!!,judging by this,im sure there is something madara didnt mention,The moon can not just throw a giant tsukuyoumi on the world,but olso throw Amaterasu,so anyone and anywhere in the world,who would defy Madara,Madara would burn with Amaterasu from the moon eye!!!!
Who agrees with my Theory??? :)