20th Century Boys was the 2nd or 3rd manga I read about six years ago, but I still regard it as the best. Recently I re-read it, intent on catching all the hints I missed on the first read. But I didn't just find early indications of Friend's identities and such, but apparent inconsistencies and plot holes. I wonder for each of these whether A: I missed or misread something, B: the scanlators left translation errors, C: it's truly the author's sloppiness, or D: intentional inconsistencies meant to resemble Friend's lies. I wonder what others make of these. Of course hidden entirely in spoiler brackets.
Spoiler
How did Katsumata (the future Friend 2) know that Kenji stole the badge from Jijibaba's shop?
At Jijibaba's shop, there are three Space Exploration Forces badges. the first is taken by Katsumata (20thCB Ch246), Kenji steals his winner wrapper (20thCB Ch247) as well as the second badge (21stCB Ch8), then one remains which is won my Maruo (21stCB Ch2). However, the shop owner says "one is missing" (earlier in 21stCB Ch2). Why not two?
There seem to be two conflicting timelines for when Sadakiyo was in Kenji & co's school. In one timeline, he transferred in during the semester of the Expo (20thCB Ch172), that is in April 1970; then met Katsumata at the time of the incident with the badges (21stCB Ch2), which was in 1970 too because the kids were grade 5 (21stCB Ch8); then had to support Fukubei in his Expo visit lie and mansion-on-the-hanging-hill mischief (20thCB Ch172-175). Sadakiyo transferred schools again at the end of this summer (for example 21stCB Ch7). However, the incident when Sadakiyo and Fukubei find Kenji & co's secret base makes for another timeline, as this was clearly in 1969 (20thCB Ch171), and Sadakiyo says he transferred schools again at the end of that summer (20thCB Ch107). The most directly contradicting parts are just one chapter apart, so this is rather unlikely to have been an unintentional error by the author.
Friend 1 = Fukubei is shot dead by Dr. Yamane on the night from 1 to 2 January 2015 (20thCB Ch133). Yet when characters later recall this (20thCB Ch227) and subsequent events like the factory explosion in Michigan (20thCB Ch216) or the assassination attempt on the Pope (20thCB Ch229) they say those happened in 2014. This is again like the 1970/1971 lie in the virtual attraction.
When the kids gather under Donkey's flag to bury the time capsule in memory of the secret base, there are two panels showing 11 kids (20thCB Ch8). Kenji, Maruo, Yoshitsune, Mon-chan, Konchi, Donkey and Keroyon can be identified clearly, Otcho's and Yukiji's presence can be inferred, but who are the remaining two? Could it be the same two unnamed boys who joined Kenji, Mon-chan, Otcho, Yoshitsune, Konchi and Fukubei to check out the ghost of the house on the hanging hill (20thCB Ch86)? (Incidentally, Fukubei's child face is shown for the first time on the same page as these boys in 20thCB Ch86.)
Who is Kin-chan who sits at a table with Kenji, Maruo & Yoshitsune at Keroyon's wedding (20thCB Ch2) but seems absent from the entire rest of the manga?
What could be the exact biological relationship of Kanna and Sadakiyo? We get plenty of evidence in several chapters that Sadakiyo is a real spoonbender. Regarding Kanna's father, although Kiriko does confirm that Fukubei is the father (20thCB Ch220), Katsumata/Friend 2 claims he gave Kiriko some medicine to give Kanna her special powers [20thCB Ch221], and when Takasu[gi] and Manjoume bring up making another child for Friend/Fukubei, they talk about in-vitro fertilization [20thCB Ch112]. Could this be an implication that Fukubei was sterile and Sadakiyo was Kanna's real biological father?