In the forty-seventh year of Wanli (1619), after the disastrous defeat of Saarhu, General Lu Tingyun returned to Shanhaiguan after a narrow escape with a secret letter entrusted to him by the war dead, only to find that the only credible recipient had already "died of a sudden illness" - a letter that no one dared to accept, leading to a treasonous grain route from the snowy plains of Liaodong to the imperial court of the capital.
