Question: Which Japanese manga series written and illustrated by Naoki Urasawa, when turned into an anima, did Mami Koyama  have a voice acting part in?
Sentence (from "20th Century Boys"): In January 2007, a sixteen chapter continuation titled 21st Century Boys (21世紀少年 , Nijūisseiki Shōnen ) ran until July, and was gathered into two "tankōbon".
Relevant evidence: No