I think this is the first time I've seen a character struggle learning to read Japanese but it must be somewhat realistic for Japanese middle schoolers learning more complex Kanji. I think Morse might've been the easiest one they've helped so far. We finally know that instead of changing the course of history they cover up for any missing parts in order to make sure it happens the way it has to, which is kinda cool but I wonder how Eiji knows where and when to go without the book.