() located in a key strategic position. It linked the North and the South and became a hub of many important traffic roads. Therefore, the sent aircrafts to fiercely raid the area of Thanh Hóa and Hàm Rồng in large extent.

During two days on April 3^rd and 4^th, 1965, the mobilized aircrafts to bomb 454 times on Thanh Hóa. The total bombs released included 627 high explosive bombs and 58 delayed-action bombs. Particularly for , the aircrafts bombed 80 times, released totally 350 bombs, and fired 149 rockets. The people of Thanh Hóa fought bravely. They incorporated with the regular army to shoot down 47 aircrafts and captured two pilots.

This was the most resounding and drastic victory that highlighted the role and position of the people's war and the very close collaboration between the armed forces, the army, the militia, and the local people. The glorious victory in Hàm Rồng manifested the iron will of Determination to defeat the invasion of the people in Thanh Hóa in particular and in Việt in general, which rejoiced the people nationwide and the progressive mankind.