Japan's first anti-hate speech law passed the Diet on Tuesday, marking a step forward in the nation's long-stalled efforts to curb racial discrimination.

But the legislation has been dogged by skepticism, with critics slamming it as philosophical at best and toothless window dressing at worst.

The ruling coalition-backed law seeks to eliminate hate speech, which exploded onto the scene around 2013 amid Japan's deteriorating relationship with South Korea.