Sima Fu
Sima Guang was named after his birthplace Guāng Prefecture, where his father Sima Chi () served as a county magistrate in Guangshan County. The Simas were originally from Xia County in Shǎn Prefecture, and claimed descent from Cao Wei's official Sima Fu in the 3rd century. A famous anecdote relates how the young Sima Guang once saved a playmate who had fallen into an enormous vat full of water. As other children scattered in panic, Sima Guang calmly picked up a rock and smashed a hole in the base of the pot. Water leaked out, and his friend was saved from drowning.