Japanese armies have consistently defeated larger Chinese forces, often outnumbering the Japanese by as much as 10 times. One Japanese Battalion (around 500-1,500) often defeats an entire division in the Nationalist army(over 10,000). One single Japanese company(100-200) could often occupy an entire town. The Japanese military strategists used this disparity(1 battalion defeating 1 division) as a standard measurement of the military strength of both sides.
The 8th route army of the Communists on the other hand, had a far more impressive display of fighting, utilizing the terrain and its mobility as an advantage. The 8th route army is organized under the San San Zhi (三三制), a system based on a ternary division. Three squad made up a platoon, 3 platoon made up a company, 3 companies made a battalion, 3 battalion made up a regiment, 3 regiment made ,ade up a brigade, 3 brigade made up 1 division, 3 divisions made up 1 army. Because of its poor equipment, the 8th route lacked firepower, but also gained mobility because of its lack of heavy equipment, especially in mountain warfare, where tanks cannot reach. The 8th route were also often fed by the local people, so their logistical were also often less problematic than their opponents. The 8th route often conducted sparrow warfare, where 1 or several soldiers harrass and take out individual Japanese soldiers before they quickly retreat. When Japanese soldiers decides to pursue these handful of men, they were often surrounded by a much larger force in the thousands and annihilated there. After the encirclement, these soldiers would immediately dissemble again.
In the March of 1939, the 115th division of the eighth route army attacked Shan Dong, annihilating a battalion of Collaborationist Chinese Army. In May, the same army crushed an encircling Japanese attack, killing over 1300. The Japanese quickly dispatched a battalion of over 600 men along with a detachment of Collaborationist Chinese army to stop the 8th route army's advance. The majority of the 115 division already left for Lu zhong Nan, leaving behind less than 600 soldiers at Lu Xi. When the Japanese reached Lian mountain, several Chinese soldiers were dressed up as villagers who led the Japanese into their village, but when the Japanese found that the village was empty, the villagers who brought them their disappeared. At this moment, a small communist force attacked with rapidness and took out a company commander and over 10 soldiers. The Japanese immediately returned fire, with their artillery and bombarded the mountain. After a while, the army sent its cavalry and Collaborationist Chinese armies forward and advanced again, when they reached the west side of the mountain when firing began again and a few dozen soldiers were killed again. But the battalion commander could not find where the fire came from. Irritated, the commander ordered the artillery to fire in all directions, and to advance to a village nearby. Search squads were sent out but could not find any trace of the 8th route army(all of whom retreated). The village was exactly where the 8th route army wanted to lead the Japanese. After midnight, the 8th route army suddenly made an attack, the Japanese tried to break out and occupy the top of the hill with 2 companies, this was blocked by the 10th company of the 115 division, and the Japanese were held there by hand grenades and human bodies after 6 attempts at charging. By the 7th attempt, the 10th company only had around 30 men left, at this moment the 11th company appeared behind the enemy and pincer attacked the Japanese forces. The Japanese company commander started to fire the artillery and attempt to break out of the encirclement, but were beaten back by a machine gun and rifles. One last assault by the 8th route army broke the Japanese line and the remaining Japanese soldiers surrendered. This is the first battle where a Chinese force defeated a Japanese force of roughly equal numbers in WW2.
As shown in the battle, the 8th route army used guerilla tactics, and often fought hand to hand combat. They use sparrow warfare and capture enemy weapons. The ability for the 8th route army to recover is also amazing; right after their strength were reduced, they often gather an even larger force from the populace. The morality is also very high in the 8th route army. Soldiers often fought to the very last man, with everyone dying, something even the IJA rarely achieves.
Towards the end of the war, when Japanese forces were weakened, the 8th route army often beat back Japanese assaults and recaptured many Japanese held towns on the country sides, even with forces that are not much larger. In fact by 1945, much of the Japanese position in the north were precarious and under the threat of the 8th route army attack. Chinese Collaborationist armies has outnumbered the Japanese forces in China by this point and often fought the communists. The communist forces were continuing to grow in strength and after the Japanese surrendered, they continued to capture Japanese held towns by force(the US informed many Japanese garrisons to surrender only when nationalist forces arrived).
If the war continued until 1950, its very likely that the Communist forces would have drove the IJA completely forces out of China the way they did to the Nationalists later in the civil war.
