 The Manchu prince-regent Dorgon (Hung Taiji had died in 1643) determined that this was the opportunity to claim the Mandate of Heaven for the Qing.Dorgon made clear in his reply that the Manchus would help Wu Sangui, but Wu would have to submit to the Qing; Wu had little choice but to accept.On May27, as the Shun army approached the Shanhai Pass from the south, Wu Sangui opened the gates to let the Qing army through the pass from the north.