Board Thread:Theories and Speculation/@comment-34656247-20180531072459/@comment-6769189-20180618031243

I dont recall Itachi ever seeing Obito use his techniques.

The curse mark could work like regular senjutsu, mixing that chakra into the users chakra, not replacing it like a junchurikis.

Itachi didnt leave his chakra inside Sasuke or his eye. He preprogrammed it to go off in response to a trigger.

When Itachi initially hit Sasuke with Amaterasu he only lit a small portion of the forest on one side of the Hideout in 390. In 394 it was shown to have spread to the rest of the forest.