WORL D WAR I I 425 ths,destroyed more than 4,000 north China villages,and killed own numbers of local peasants.The destruction of the dikes changed course of the Yellow River,which since the 1850s had flowed into the wSea north of the Shandong peninsula.Now the waters again fol- dthe southerly course and flowed across the northern part of Jiangsu ore reaching the ocean. By the late summer of 1938,however,the Japanese had assembled the s tanks,and artillery needed for the final assault on the tricity area of han.Fighting took place at scores of locations north and east of the city amost five months.The Japanese brought reinforcements by rail from north,and by convoys of armored boats along the Yangzi,which they matically cleared of Nationalist defense positions.Once they had embled the vessels needed to sweep Boyang Lake,which the Nationalists mined,they also were in a position to attack Wuhan from the south. The tricities might have fallen far sooner had it not been for the heroic ons of the Russian pilots sent to China by Stalin,whose renewed concern Nationalist China's survival could be traced to the anti-Comintern alli- of Germany and Japan.The Russian flyers'main base was at Lanzhou Gansu,where they received supplies brought by truck and camel over old Silk Road;in several pitched air battles-and on occasion through aning ruses-they inflicted severe damage on the Japanese air force. But by late October 1938 much of Wuhan was in ruins.Chiang Kai-shek, ohad readied yet another wartime base,this time deep beyond the angzi gorges in the Sichuan city of Chongqing(Chungking),was flown of the city to safety there,while those troops who could do so commenced ir retreat.The Japanese took over the ravaged area on October 25,1938, ing(according to Chinese estimates)sustained 200,000 casualties and lost ore than 100 planes.Only four days before,Japanese marine and naval ts had landed and seized Canton.Chiang Kai-shek had now lost de facto ntrol over the whole swathe of eastern China stretching from the passes Shanhaiguan to the rich ports in the semitropical south,along with all wealthy commercial and industrial cities lying in between.The area compassed the most fertile of China's farmland and the ancient cultural eartland of the country. CHINA DIVIDED By 1938 the great expanse of territory that had once been a unified empire ander the Qing was fragmented into ten separate major units:Manchukuo, the Inner Mongolian Federation,northeast China south of the Great Wall