Logic and reason were no longer found when Yuri is in the presence of his sister... he was neither smart nor dumb,

You quietly sat in the break room, reading a book. you were engrossed by the contents of every page it took. Meanwhile, Yuri was off alone playing chess like the mute he'd been, not a peep of a mess.

He thoughtfully moved his chess pieces, all strategy and tactics he tried to piece. He thought of every move he had to make every possibility for the board to make.