Daily Chinese Idiom Guessing Game
Passed on by word of mouth from person to person.
不著文字，口头相传。
宋·张君房《云笈七签》第七十二卷经云‘知白守黑，神明自来。’是知玄为万物母，圣人秘之，不形文字，口口相传。”
The story of the old town has been passed down by word of mouth for generations.