▁Che - y uan , ▁defect ed ▁back ▁to ▁the ▁Japanese ▁side ▁again . ▁Li u ▁was ▁given ▁the ▁title ▁of ▁" B and it ▁Supp ression ▁Commander ▁of ▁Eastern ▁Ch ah ar ", ▁command ing ▁three ▁reg iments ▁station ed ▁at ▁Ch ich eng , ▁D ush ik ou ▁and ▁Y un z hou . ▁ ▁Li u ' s ▁force ▁blocked ▁Tang ' s ▁troops ▁from ▁following ▁the ▁rest ▁of ▁the ▁Anti - J apan ese ▁Al lied ▁Army ▁south , ▁leaving ▁F ang ▁Z hen w u ▁and ▁Ji ▁Hong ch ang ▁to ▁continue ▁alone . ▁ ▁On ▁September ▁ 2 5 , ▁F ang ▁Z hen w u ▁attacked ▁and ▁occupied ▁Ga oli ying . ▁ ▁A ▁Japanese ▁reconna issance ▁aircraft ▁dropped ▁a ▁warning ▁to ▁withdraw ▁from ▁the ▁Tang gu ▁Tre aty ▁dem il itar ized ▁zone ▁the ▁following ▁day , ▁and ▁when ▁he ▁failed ▁to ▁do ▁so ▁on ▁September ▁ 2 7 , ▁Japanese ▁aircraft ▁bom bed ▁his ▁position . ▁ ▁F eng ▁and ▁Ji ▁decided ▁to ▁continue ▁the ▁advance ▁with ▁their ▁remaining ▁ 6 , 0 0 0 ▁men , ▁( appro xim ately ▁half ▁un ar med ), ▁divided ▁in ▁three ▁groups . ▁ ▁At ▁the ▁beginning ▁of ▁October , ▁Ji ' s ▁forces ▁encountered ▁the ▁forces ▁of ▁Shang ▁Z hen , ▁Gu an ▁Lin zh eng ▁and ▁P ang ▁B ing x un ▁at ▁Ch ang ping , ▁blocking ▁their ▁further ▁advance . ▁In ▁a ▁few ▁days ▁they ▁had ▁surrounded ▁the ▁Anti - J apan