In the official anime, Itachi and Obito first met during a mission. The official meeting with Obito was before Itachi's clan was exterminated. It was also this time that Itachi also learned about the underground organization Akatsuki and Obito's disguised identity Uchiha Madara .
Obito revealed his true strength after Itachi's death, so I don't think Obito was afraid that Itachi would hinder the Eye of the Moon plan. Of course, it could also be that there was no need to hide it at that time. If Itachi can hinder Obito in the early stage, it may be because he is afraid that the plan will be leaked. I also prefer that Itachi can contain Obito in terms of strength. If not, Obito can completely kill Itachi to avoid future troubles.
Obito had a kaleidoscope and white Zetsu body, wood escape , fire escape and the collected Sharingan. Obito's body is better than Itachi's, which does have advantages in this aspect, as well as divine power and virtualization. Hashirama's cells greatly reduce the side effects of Sharingan . On the other hand, Itachi's body is not very good. For Obito's true strength I don't know much about him, but there is a certain gap between him and Obito in terms of strength. From this point of view, Obito shouldn't be restrained by Itachi. But in the anime, Itachi did try to contain Obito.
Itachi must first of all know that Obito will have divine power and virtualization, and the collection of Sharingan. The combat strength information of the enemy and ourselves in the early and mid-term can sometimes influence the war. Obito must know that Itachi can fire and water escape, Amaterasu, month reading . Amaterasu is similar to illumination on objects, while Tsukuyomi is a momentary illusion, a kind of mental attack. Amaterasu and Tsukuyomi are Hollows that completely restrain Obito. Moreover, there is a difference in pupil power between double kaleidoscope and single kaleidoscope. Double kaleidoscope is greater than single kaleidoscope. Obito probably knew that the Double Kaleidoscope could activate Susanoo, but he probably didn't know the strength of Susanoo and . Susanoo itself has individual differences. Knowing that Itachi could activate Susanoo, Obito wouldn't touch Itachi easily.
Itachi also possesses the spiritual weapon of Eight-foot mirror Ten-fist sword. With the Eight-foot Magatama move, it is very difficult for Obito to escape unscathed. Itachi also has a move like Izanami (Itachi may also use Izanami, let’s not mention other gods). It would be difficult for Obito to win without knowing this move. Some people also say that you can use Kamui to make a surprise attack or directly throw Itachi into time and space. This is still quite risky because you need to get close to absorb it. At this time, Itachi's Amaterasu, Tsukuyomi, and Susana Nenghu was extremely good at attacking Obito. Itachi knew Obito's Kamui skill, so the chance of success was too low. Itachi knew Uchiha Madara (Obito)'s identity, and Itachi himself would not act rashly. In this case, Obito would just wait and see Itachi's actions.
Obito must monitor the battle between Itachi and Sasuke, because this battle will have an impact on Eye of the Moon plan , because if Itachi wins this battle, then Itachi will have the opportunity to become the Eternal Kaleidoscope, and Itachi will It is possible that he directly attacked Obito. At that time, Obito basically had no chance of winning against the Eternal Kaleidoscope. This meant Itachi had to die after this battle, but Obito didn't fully expect Itachi would die.
Itachi himself needed to figure out what Obito's plan was before he could fundamentally solve the plan's implementation. Obito knows that Itachi will not attack him easily, nor will he attack him personally, and Itachi's strength does indeed deter Obito. Obito also knows that Itachi's health is not good, so he only needs to Delay the plan and drag Weasel to death.
Itachi's ability to contain Obito is the main part, and it also affects the implementation of the plan. It would be disadvantageous for Obito to confront Itachi head-on.
