With righteous blood and a loyal heart, he served his country.
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history
From the 庄子 (Zhuangzi) story of Chang Hong 苌弘, a loyal Zhou minister wrongly executed; his blood, buried for three years, was said to turn into 碧玉 (bìyù, jade-green stone). 碧血 became literary shorthand for unjust death in service of righteousness.
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Strongly literary and elevated. You will see it on monuments, in eulogies, and in the fixed phrase 碧血丹心 (bìxuè dānxīn, righteous blood and loyal heart), not in everyday speech.
