ICv2 compares the size of the bumps enjoyed by Naruto and Bleach after their Cartoon Network debuts:
“Comparing the first four weeks of Bookscan sales after the first appearance of the Cartoon Network effect, sales of Bleach Vol. 1 were 52.4% of the numbers attained by the first volume of Naruto in 2005.”
The piece goes on to analyze some of the factors that may have led to the slighter performance for Bleach, including the fact that it has more than twice as many volumes in print as Naruto did when it started airing in September of 2005.
Though the article doesn’t mention it, the performance of Fullmetal Alchemist would seem to bear this out. The anime’s debut preceded the release of the manga in that case, so there was no catching up needed.
Another factor that isn’t considered in the Naruto-Bleach comparison is the fact that Naruto has a much better time slot. Airing at 9 p.m. on Saturdays surrounded by similar programs, supported by lots of commercials, has to give it some kind of advantage over a show that runs at midnight. And I’m pretty sure Cartoon Network doesn’t advertise Adult Swim programs during its daytime programming.
And while it’s probably nowhere near as significant, it can’t hurt that Naruto is serialized in Shonen Jump, making it cheaper to sample if someone isn’t certain they want to make the jump from anime to manga.
Still, the Bleach bump isn’t exactly insignificant, even if it isn’t astronomical. As ICv2 notes:
“Naruto gives every appearance of being a once in a lifetime phenomenon, at least in terms of manga sales in the U.S. market, and its brilliance shouldn’t blind retailers to the promise of Bleach (or Death Note, another Viz Media property with immense potential).”
Good point about Death Note, which has popped up on the BookScan charts and doesn’t even have an anime version available in English. (Yet… the anime just debuted at the beginning of this month in Japan.)