The clash between Toru Hashimoto and the weekly magazine Shukan Asahi over an article on the Osaka mayor's lineage has raised a question that Japan still refuses to directly confront: What kinds of comments cross the line from criticism into hate speech that should be legally banned?

Shukan Asahi's article last month delved into Hashimoto's family background, noting his father was a yakuza. But it also added his father was a descendant of the feudal period "burakumin" social outcast class, which was traditionally shunned in Buddhist society because its members engaged in jobs considered unclean — butchers, tanners, undertakers.

The article broke no new ground, as the story of Hashimoto's father and his burakumin roots had appeared in monthly and weekly magazines last year.