Board Thread:Theories and Speculation/@comment-31099706-20170327120301/@comment-26127155-20170425111511

@BlazeRelease

Edit: So sorry for the length of this post.

You made some great points. The main reason that I believe that he wouldn't risk ending the battle so early, is because Itachi was ridiculously fixed on the idea of dying by Sasuke's hands.

As a major point, I don't think this is a separate "watered down" version of Tsukuyomi. Every technique can be used with a varying array of expertise. Itachi in these scenarios is, holding back his techniques so he doesn't go overboard with the damage he does. He always walks the fine line between looking serious, and not outright killing his allies (Leaf ninja and Sasuke).

1.Itachi's core character flaw was forcing Sasuke on this crazy vendetta rather than being open with his younger brother. He spent nearly a decade of deceiving every one of his true intentions, and even managed to trick Sasuke, Kisame, the Uchiha, & Kakashi about who he was as a person.

Orochimaru in the grand scheme of things, was not a major threat to Itachi. He had to be extracted at some point in that battle, but Itachi always had his trump card (Susanoo) waiting for Orochimaru.

When I went back and analysed the battle again for small details, I found it is interesting how Itachi shifts the flow of the battle from the different ninja arts (Shurikenjutsu, Ninjutsu, Genjutsu, etc). It almost looks like Itachi used this battle as a final test to Sasuke, to prepare him from the likes of Orochimaru, Danzo, and Madara. He certainly pushed Sasuke hard, but always seemed to ease up whenever Sasuke was in any major trouble.

2.Tsukuyomi has definitely been used in a "pulled punch" manner throughout the series. The only time Itachi went for the kill in the series was in the Uchiha massacre. He was able to distort time and space in that scenario to the extent that Izami's brain was not able to process the information quick enough which lead to her death (as well as her body thinking that she died of natural causes). Even this version was merciful compared to using that time to constantly torture his victim.

Sasuke (as a child) would have been dead if Itachi didn't "pull his punch" with that Tsukuyomi. Itachi didn't want to kill the likes of Kakashi and Sasuke, and logically wouldn't have tried to kill either of them.

3.Sasuke is one of the smartest characters in the series, but he was not able to tell Itachi's true intentions for nearly a whole decade. It honestly would be more surprising if Sasuke noticed anything different, especially considering Sasuke was tunnel visioned by his Revenge.

4.Genjustu can't usually kill a person, but Itachi has been shown to be able to accomplish this feat (against someone with a fully matured sharingan as well). Incapacitating (even extremely fatiguing) Sasuke would have ruined the whole point of the fight.

The main explanation for the Ameterasu part of the fight, is that Itachi was aware of some techniques that Orochimaru would have passed on to Sasuke (as Orochimaru is a pain in the ass to kill). Another explanation, was that Itachi had a method for removing the flames from Sasuke if it really got to that extreme point (removing flames like Sasuke, fire sealing like Jiraiya, or possibly Totsuka blade?).

Itachi couldn't expect this level of defence from Genjutsu though considering Sasuke's two major mentors (Kakashi and Orochimaru) stood no chance against Itachi's Sharingan abilities. Orochimaru in particular was laughable in terms of going against Itachi's genjutsu (Itachi using base sharingan, and not even making eye contact completely immobilising him).

5.Genjustu (and in particular Tsukuyomi) had to be used in this fight. It's his trademark ability and it's a part of his identity. Not using this ability would have been a colossal red flag, and even watchers of the series would've probably been genuinely pissed off if a character didn't use their signature ability in a fight. This is like Naruto not using the shadow clone justu in a fight, it just would have been way to obvious that something was off.