Controversy has been sparked by a volume (volume seven) of the American football manga Eyeshield 21 (a Shonen Jump manga published in the US by Viz Media) since it apparently contains what some readers claim to be a "racist" and "humiliating" depiction of black people.
Of course this is not the first time manga readers have been offended the stereotypical appearances of black characters in anime and manga, the most infamous of which is (the servant) Mr. Popo from Akira Toriyama's ever popular Dragonball (Z) series; eventually Viz had to edit the US release of the Dragonball manga themselves to reduce the size of Popo's lips.
Of course this is not the first time manga readers have been offended the stereotypical appearances of black characters in anime and manga, the most infamous of which is (the servant) Mr. Popo from Akira Toriyama's ever popular Dragonball (Z) series; eventually Viz had to edit the US release of the Dragonball manga themselves to reduce the size of Popo's lips.