In Yakuza culture, tattoos (also called irezumi) are extremely important. Drawing inspiration from Japanese woodblock designs and mythology, they serve a great purpose in expressing a Yakuza member’s personality and position in the organization (via Tattmag). While the Yakuza are far from the only people in Japan to get tattoos, having them is still heavily stigmatized in Japan and other East Asian countries, including China. However, China has taken its stigma a bit further than others.
According to IGN, China actually banned actors from getting tattoos in 2018 (as well as any depictions of hip-hop, subcultures, or decadent lifestyles). As part of the move, Chinese censors removed all of Tatsu’s tattoos, leaving him as bare as the day he was born. In doing so, of course, Tatsu loses one of his defining visual elements and characterizations.
Being an ex-gangster is basically Tatsu’s whole character. Removing his tattoos just makes him feel less like a gangster than before. And even if that was the goal of the Chinese censors, it really waters down his character. If the ex-gangster can’t look like a gangster or represent the Yakuza subculture, then there’s really no point in airing the show.