Battle of Shanggao The Battle of Shanggao ( ) was one of the 22 major engagements between the National Revolutionary Army and Imperial Japanese Army during the Second Sino - Japanese War . On the March 14 , 1941 , the Japanese 11th army attacked the headquarters of the Chinese 19th army . Fierce fighting broke out , and a series of bloody see - saw battles broke out as both sides contested the position . On March 15 , after the base was lost to the Japanese , A Chinese air strike destroyed Japanese food and ammo reserves , demoralizing the Japanese and stalling their attack on the Chinese troops , who used this opportunity to dig new defensive positions . The Chinese positions now contained some 100 , 000 troops , in three main defensive lines of trenches and concrete - supported bunkers . Even though the Japanese still clung on to the Chinese headquarters , the Japanese commanders were determined to achieve total victory by destroying or capturing all Chinese units , and to do this , it was necessary to breach the Chinese lines . On the 17th , the Japanese attacked the first of the three Chinese defensive lines , but were repeatedly turned back by the dug - in troops and their heavy machine - gun fire . The Japanese suffered heavy casualties that day , and the next day they advanced behind a smoke screen . The Japanese managed to get to the Chinese lines , and vicious hand - to - hand fighting broke out . Both sides suffered heavy losses , but in the end , the Japanese managed to breach the Chinese first line of defense . After capturing the first Chinese line of defense , there was a lull in the fighting as both sides tended to their wounded . The Japanese called in more reinforcements , while the Chinese rushed in troops from the third line to the second line of trenches to bolster their defense . On March 22 , the Japanese launched an air strike on the Chinese defensive line , resulting in some 100 - 200 Chinese dead or wounded . Then , they advanced with tanks and armored cars , followed by infantry . However , the Chinese managed , to destroy approximately half of the tanks and killed the infantry behind them with small - arms fire . The Japanese were forced to retreat , and then launched a poison - gas attack . Unfortunately for the Japanese , the Chinese had already expected this move , and had abandoned the second line of trenches and fallen back to the third line of trenches , minimizing the casualties taken from the gas attack . On March 24 , the Japanese launched an all - out assault on the Chinese , by throwing in all of their remaining planes , tanks , and infantry . The Chinese responded with mortar attacks and machine - gun fire , plus their own planes to combat the Japanese planes . The losses on both sides were heavy , with experts thinking that both sides suffered the most casualties on that day . The Japanese had a number of advantages , including tanks , better training for their troops , and better weapons . However , the Chinese greatly outnumbered the Japanese , due to the Chinese general , Zhu Xiang , rushing in troops at the last moment . At the end of the day , the Chinese lines were still in Chinese hands , and the Japanese attack had been repelled . After reevaluating the situation , Japanese tacticians concluded that they could not afford to suffer any more losses from what was considered to be an inconclusive battle about the trivial matter of a Chinese headquarters , and on 1 April , they began to withdraw . In haste , the Japanese left behind many of their weapons and wounded troops . They would be soon be captured by the Chinese . . By the 19 April , the withdrawal was complete , and both sides now occupied their original positions . In conclusion , the battle ended with a decisive victory for the Chinese forces , who were able to capture substantial amounts of military equipment and supplies , and boost the morale of the Chinese people .