The whole poem:
望门投止思张俭，
忍死须臾待杜根。
我自横刀向天笑，
去留肝胆两昆仑。
张俭 and
杜根 were Han officials who survived persecution, one by fleeing from house to house and one by playing dead; the last line says that those who flee and those who stay are equally brave. When the Hundred Days' Reform was crushed,
谭嗣同 refused to escape and was executed on 28 September 1898, one of the
戊戌六君子.
