包黑脸断案子 bāohēiliǎnduàn'ànzi [xiehouyu] to ignore personal connections for the sake of justice
A two-part allegorical saying meaning to show no favoritism. Like the legendary official Bao Zheng (Bao the Black-Faced), who judged cases with strict impartiality and ignored personal ties or social status when enforcing the law.
