Board Thread:Naruto Discussions/@comment-1872728-20160329033053/@comment-5407586-20160502071255

QuakingStar wrote: "イタチの命と引き換えに、サスケは直巴の〝万華鏡写輪眼” を開眼. " = "In exchange for Itachi’s life, “Chokutomo”/Straight tomoe of the Mangekyou Sharingan were awakened." Wait. This passage could also be interpreted as "Because of Itachi's death, Sasuke awakened the Choku Tomoe Mangekyō Sharingan".

Though I agree that Choku Tomoe=Eternal Mangekyō Sharingan.