During the winter of 1933, the Chinese Army was falling back, being pushed south out of Manchuria by the Japanese army. In order to buy the main army time to retreat and regroup, the Dadao Dui (Big Knife Unit) was ordered to ordered to protect a 30 mile segment of Great Wall at Xifengkou, a strategic stronghold, and 1 of 3 important passes.
The Dadao Dui, formerly known as the 29th Army Corp, was under the command of Capt. Song Zheyuan. When Japanese Guangdong Army attacked, the out numbered, out gunned 29th dug in to meet them, with Capt. Song writing. "I'd rather be a dead ghost than surrender." After heavy loses on March 9, the 29th decided that a sneak night time attack was their best strategy. At midnight, two groups of soldiers, totaling 500 men, took up their dadao with the orders, "Only forward, no retreat, until you die."
With both sides exhausted from the day's fighting, the Japanese were not expecting an attack and were caught off guard as the 500 attacked from two directions. Caught totally off guard, the Chinese killed many hundreds of Japanese in their sleep, capturing more than 10 machine guns & setting fire to supply vehicles. But this first of Chinese victories in the war did not come without its costs. Of the 500 men of the Dadao Dui who attacked that night, only about 30 survived.
Their sacrifice saved their comrades and clearly demonstrated the Dadao to be a very effective, close quarter weapon when facing katana and as a tool of ambush, even in an age of modern warfare (where most rifles being used were bolt actions). Indeed, the dadao was such an effective weapon that special steel collars were issued to Japanese frontline troops.