Some of these kids don't understand that the iron skin is a jutsu, or for some reason they think the sharingan is an actual jutsu in and of itself. It allows for jutsu to be used through it, but it isn't a jutsu.Dafuq. Im not sure why people are saying iron skin or mentioning his hearts.
Op said taijutsu. Iron skin is ninjutsu. His other hearts use ninjutsu therefore why people keep mentioning this ive no idea.
Anyway the clear cut winner here is itachi.
He has already blitz 3 sharigan users in the konoha police force and defeated them with taijutsu at 12.
Now everything else is in favour of a clear cut win.
Itachi has the taijutsu advantage this is backed by the databook.
Kakuzu has a 4, itachi has a 4.5
Speed also comes into a taijutsu fight and again has the advantage.
Kakuzu's speed is 4, whilst itachi's is a 5.
Handspeed also comes in quesion because taijutsu is basically hand to hand combat therefore somebody with faster handspeed has the advantage. Itachi has demonstrated the fastest hadnseepd movement in the series and has a 5. Kakuzu has a 3.5.
All this alone should tell you that there is a clear winner. Now if you add the sharigan into this, it makes this already clear cut fight, even clearer because itachi's reflexes increases a considerable amount and with that would overwhelm kakuzu is a taijutsu fight