iron walls and brass partitions
Tiebi Tongshan, a Chinese idiom, Pinyin is ti ě B ì t ó ngsh ā n, which means a strong and reliable force. From "knight errant biography · knight errant circle".
The origin of Idioms
Qing Ganxing's "knight errant biography · knight errant circle" said: "these two big heads are my iron walls and Tongshan. Don't these little officials let me do it freely?"
Idiom usage
It is often used in figurative sentences.
iron walls and brass partitions
the voice of singing reverberates round the beams of a house for days - gē shēng rào liáng