Why didn't the Northeast Anti-Union establish a base area, and then it was almost completely annihilated?

The main population is immigrants, who are concentrated in cities, around traffic lines and some big villages. Therefore, it is not conducive to guerrilla warfare, but to the occupation forces. The enemy's traffic in plain areas is smooth, there is no shelter, and the natural environment in mountainous areas is harsh. However, under such circumstances, the Northeast Anti-Union was indeed based at the beginning, such as Yanshi, Bayan, Jiguan Mountain and so on. There are garment factories, arsenals, field hospitals, radio stations and so on. The enemy is really too powerful, but even so, the Northeast Anti-Union War cost them a lot, and more than 100,000 Japanese puppet troops died at their hands. Of all the armed forces of the * * * production party, the Northeast Anti-Union has the lowest average combat casualty ratio, which is lower than that of the New Fourth Army and far lower than that of the Eighth Route Army.