Lu Mao, a native of Wu Commandery during the Three Kingdoms period and younger brother of the famed general Lu Xun, lost his father in childhood and lived with their great-uncle Lu Kang. After Lu Kang went to war with Yuan Shu, Lu Mao returned to his ancestral home in Wu County. Having endured a childhood of hardship and displacement, he grew into a man deeply sympathetic to those who shared his fate and was always eager to help them.
During the Three Kingdoms period, Lu Mao of Wu Commandery cherished friendships with several ambitious but impoverished scholars: Chen Rong from Chen State, Puyang Yi from Chenliu, Jiang Zuan from Pei Commandery, and Yuan Di from Guangling. Though none were wealthy, all shared lofty aspirations and spirited temperaments. Lu Mao, despite his own modest means, would always share whatever fine food, clothing, or goods he obtained with his friends, insisting, "When we enjoy the good, we share the hardship together." They would gather to discuss history and critique current affairs, their bond strengthened by mutual respect and generosity.
When Lu Mao's uncle Lu Ji passed away at just thirty-two, he left behind two sons and a daughter, all only a few years old. Lu Mao took them into his own home and raised them until they were grown, only then allowing them to live independently. Later, Lu Ji's eldest son became a commandant in southern Kuaiji, and the second son served as a colonel of the Changshui garrison—both achieved great success.
Lu Mao was known throughout his county for his generosity and kind heart. When Xu Hou, an imperial censor from the same region known for his outspoken honesty, lay dying, he worried about his children. Though they had never met, Xu Hou had heard of Lu Mao's character and wrote a letter entrusting his children to him. After Xu Hou's death, Lu Mao built his tomb, then brought the children into his own home, letting them eat and sleep alongside his own kids, treating them as his own. He hired tutors to teach them the classics and personally instructed them in moral principles. To focus on their upbringing, Lu Mao repeatedly declined official posts offered by the prefecture and commandery. Under his influence, the children grew into learned, ambitious individuals, becoming a celebrated local legend.
Later, the idiom "strangers to each other" came to be used to describe people who have never known or been familiar with one another.
Source: *Records of the Three Kingdoms*, "Biography of Lu Mao"
Meaning of the Idiom: Later, the Chinese idiom "素不相识" came to describe people who have never known or been familiar with one another.