CoroCoro is actually closely connected with pokemon, running several comics over the years, but that's besides the point. Think about it like this. You know how whenever we get a Nintendo Direct or E3 comes around and that's where the reveals and new info come from? well that's what CoroCoro is in magazine for. When GF wants to release new information and produce hype, they give the info to CoroCoro and they publish it, just like other gaming magazines do in the states. The magazine and videos normally are supposed to be released at the same time, but someone one the inside gets their hands on a copy, scans it and uploads it to the internet before it even releases, becoming a leak.
"Impossible is just a word people use to make themselves feel better when they quit." ~Vyse, Skies of Arcadia
