sentences:  The loss of the position at the railway junction signaled that the defensive force inside the city must be strengthened and Lin Biao immediately did so, and informed the defenders in the city.The arrival of the reinforcements greatly boosted the morale of the defenders and the advance guard of the 21st Regiment of the 7th Brigade of the communist Western Manchurian 3rd Division launched a counterassault on the nationalists with the help of other communist units, and successfully took back the positions at railway junction previously lost on the same afternoon, while inflicting heavy casualties on the nationalists in the process, and the heavy casualties stopped the offensive of the nationalist 30th Division completely.After the struggle for Siping had begun, both Chiang Kai-shek and Mao Zedong in their distant headquarters were concerned about the development and both frequently inquired the progress on the battlefield.