Big Comic Spirits
Written and illustrated by Naoki Urasawa, "20th Century Boys" was originally serialized in "Big Comic Spirits" from 1999 to 2006. The 249 individual chapters were published into 22 "tankōbon" volumes by Shogakukan from January 29, 2000, to November 30, 2006. A sequel, titled "21st Century Boys", started in "Big Comic Spirits"s January 19, 2007, issue and ran until July. The 16 chapters were released into two volumes on May 30, 2007, and September 28, 2007. "20th Century Boys" received an eleven-volume "kanzenban" re-release between January 29 and November 30, 2016. The single "kanzenban" reprint of "21st Century Boys", released on December 28, 2016, includes a new ending. A one-shot manga titled "Aozora Chu-Ihō" ("Blue Sky Advisory – Kiss") was published in the February 2009 issue of "Big Comic Spirits", it was credited to "Ujiko-Ujio", the pen-name of the fictional manga creator duo Kaneko and Ujiki in "20th Century Boys".