The meaning of this sentence is: After hearing this sad farewell song, the three hundred thousand soldiers stationed at the border all raised their heads and looked at the rising moon.
Source: Li Yi of the Tang Dynasty, "Joining the Army in the Northern Expedition"
Original poem:
After the snow in the Tianshan Mountains, the sea is windy and cold, and the flute blows sideways, making it difficult to travel.
Qili recruited three hundred thousand people, and for a while they looked back at the bright moon.
Translation:
It snowed heavily in the Tianshan Mountains, and the wind blowing from Qinghai Lake made it even colder. During the march, the soldiers played the flute song "The Journey Is Difficult." Hearing this sad farewell song, the three hundred thousand soldiers stationed at the border raised their heads and looked at the rising moon.
Extended information:
During the Mid-Tang Dynasty, Heshuo, Youzhou, where Li Yi joined the army, became a separatist place. The soldiers stationed here had to protect their families due to years of war and long-term border fortress garrison. The ambition to defend the country and make contributions to the country has sadly disappeared, and has been replaced by the resentment of war weariness and longing to return home. Li Yijiu was in the army and had a deep understanding of this. This frontier fortress poem prominently expresses the homesickness of the conscripts who have been garrisoned for a long time.
In the poem, the author constructs an extremely difficult typical environment with the characteristics of a frontier fortress, creating a sad and desolate atmosphere. Through the use of exaggeration and vividness, the scene of the soldiers listening to the flute and homesickness is brought to life. When depicted, the scenes complement each other, vividly and truly expressing the melancholy of returning home. The artistic conception is desolate and majestic, the atmosphere is sad and moving, and it is sad to read. Li Yi's poetry has excellent works in all styles of poetry in ancient and modern times, but his "seven character quatrains" have the highest achievement, which can be seen in this poem.