When does Qingming open the tomb door?

From "opening the tomb door" at the vernal equinox to "closing the tomb door" on the eighth day of the fourth lunar month. You can go to church every day during the period. However, the "new grave" sacrifice should not be later than after the Qingming Festival, and it is said that "the new grave is unclear". The so-called "new grave" refers to the newly built grave after sweeping the grave last year. Including new mourners and reburied people. Any "new grave" must have a "New Year's Eve dinner" on that year's eve, and no one may violate it.