朱云折槛

(idiom) Zhu Yun breaks the railing (Zhu Yun was a Han Dynasty official who accused the emperor's tutor of corruption, and when sentenced to death, clung to the palace hall railing so fiercely while demanding justice that he broke it); (fig.) to speak the truth with unwavering courage; to admonish fearlessly

also pr. [zhu1yun2-she2jian4]