 They allowed the Japanese to occupy the city almost without resistance.Only a few units under Sun's command refused to retreat from Lingyuan and fought the Japanese to the death, while he moved his army to Chahar Province.As the entire Chinese defense of Jehol collapsed, some of Sun's units lost contact to their headquarters and were left behind; one of his regiments consequently launched a counter-attack on Chifeng, not knowing that other NRA forces had already fled the province.