It refers to the twice-daily chanting and sutra recitation that Nichiren Buddhists do. During his lifetime, people hated Nichiren's guts. He was a sage and scholar in medieval Japan. He would send letters to the government and tell everyone that terrible things would happen if people ignored the Lotus Sutra. People got pissed off.
Nobody likes to be criticized.
One night, an army showed up at Nichiren's house to kill him. The soldiers took him to a deserted beach. Just as they were about to cut off his head, a fireball fell out of the sky. The soldiers freaked. No one dared raise a sword against Nichiren.