Describe the dangerous terrain, easy to defend but difficult to attack. What idiom is it?

Idioms that describe the difficult terrain are Iron Wall, Jincheng Tang Chi, rock-solid, indestructible and so on.

First of all, an iron wall

Interpretation: The original metaphor is very defensive and indestructible. This is also a symbol of unity.

Source: Shi Naian's "The Biography of the Water Margin" The 48 th time: "Song Jiang led the troops in the front. When he turned to the back of Dulonggang to see Zhujiazhuang, there was an iron wall behind him, which was neatly arranged."

Second, Jincheng Tang Chi

Interpretation: metal city wall, boiling water moat. Metaphor is extremely strong and well-defended cities or fortifications.

Source: The flashy Chinese Art Museum III: "With a good brother and helper like you, Xian Xia is Jincheng Tang Chi, and the Manchu people can't get through with their wings!"

Third, rock-solid.

Interpretation: as firm as a rock, it means that it cannot be shaken.

Source: Peacock Flying Southeast in the Han Dynasty Anonymous: "The rock is thick and can die for thousands of years."

Emotion is rock solid, even if you lie there for a thousand years, it will not change its tenacity.

Fourth, indestructible.

Interpretation: Very strong and indestructible.

Source: Ye Xie's "On the Original Poetry" in the Qing Dynasty: "Only strength can be strong, so it is indestructible."

Only when you are strong can you be stronger, so your firmness will not be destroyed.

Five, the tiger in the dragon brand

Interpretation: Describe the majestic and dangerous terrain.

Source: President Mao Zedong's "The People's Liberation Army Occupy Nanjing": "The tiger and dragon win the past and reverse the generosity."

Nanjing, the city of the emperor, is better today than in the past. In the face of earth-shaking changes, I can't help but be excited and passionate!