[走后门 / 走後門, zǒu hòu ménㄗㄡˇ ㄏㄡˋ ㄇㄣˊ] lit. to enter by the back door; fig. to gain influence by pull or unofficial channels; back door or under the counter connections#44371
[开后门 / 開後門, kāi hòu ménㄎㄞ ㄏㄡˋ ㄇㄣˊ] to open the back door; fig. under the counter; to do a secret or dishonest deal; to let sth in by the back door#71872