All hentai produced in Japan is censored by law. The law discourages showing genitals in hentai and all other forms of pornography. This is why most hentai will make use of black bars, mosaics, or a blur effect to hide genitalia. That said, you will find hentai with this tag completely uncensored. This is accomplished by having artists go in afterward, remove the censorship, and redraw the missing parts.