Ennin's eyewitness diary and official Tang records document the persecution's scale in detail, including the 260,500 monks and nuns returned to lay life, but neither they nor any later Chinese history drawing on them records a death toll.
What would resolve this A documented count from Tang administrative or local records of deaths directly caused by the persecution, distinct from the well recorded laicization total, should one ever surface in the surviving archive.
OpenTang dynasty history; Chinese Buddhist historyEnnin, translated and annotated by Edwin O. Reischauer, Ennin's Diary: The Record of a Pilgrimage to China in Search of the Law