iron bastions
Tongcheng Tiebi, a Chinese idiom, is pronounced t ó ngch é ngTi ě B ì. It originally means that the defense is very strong and indestructible. It's also a metaphor for unity. It is the same as "iron wall". It's from the strategy of frontier defense in three provinces.
The origin of Idioms
According to Yan Ruyi's strategy of border defense in three provinces in Qing Dynasty, "those who make fortresses among the people are also ordered to follow suit, and they are located in the iron wall of the Tongcheng."
Word usage
Be subject or object
Chinese PinYin : tóng chéng tiě bì
iron bastions
introduce comic remarks in dialogue. sā kē dǎ hùn