Is “Yielded the throne to his brother Boyi and died for the Zhou cause” true?
attested in history
Records of the Grand Historian, 'Biographies of Boyi and Shuqi', says their father wanted Shuqi to succeed, but Shuqi yielded to Boyi, who fled; Shuqi also fled. Later they both remonstrated with King Wu and starved to death on Shouyang Mountain.
Shu Qi
In history, he and his elder brother Boyi yielded the throne to each other and starved to death for righteousness; in fiction, they are equally portrayed as paragons of virtue.