I happen to have a book right now with me called "The Jews and the Japanese" by Ben-Ami Shillony (1992) where there is alot of talk on Jews in Northern China and Shanghai.. some excerpts..
The number of Jews in China is not great, but their influence on the Chinese economy is immense, and they maintain covert links with powerful Jewish politicians, businessmen, and journalists in the U.S., Britain, and other countries." It was this pragmatic principle of using Jewish power for the benefit of Japan that guided Japan's policy toward the Jews during World War II.
While there were only a few Jews who stayed free in Japan during the war, tens of thousands came under Japanese rule on the Asian continent. When the Japanese occupied Manchuria in 1931, they found a thriving Jewish community of thirteen thousand, most of them in the city of Harbin. These were Russian Jews, some of of whom had settled there at the beginning of the century and others who had fled from the Russian revolution. The Harbin Jews led a rich communal life, maintaining several synagogues, religious schools, a Jewish hospital, two Jewish banks, and two Jewish journals.
After the Japanese occupation, business opportunities worsened, and many Jews left Harbin for Shanghai and Tianjin, but the five thousand who remained were allowed to maintain their social and religious institutions. The Guandong army, which controlled Manchuria, was also in charge of the Jews. In 1933 the intelligence section of the Guandong army, the Tokumu Kikan, conducted a study of the Jews and reached the conclusion that although they were few in number, Manchurian Jews wielded considerable power and that it would therefore be in Japan's interest to treat them well. In December 1935 the Japanese consul general in Harbin, Sato Shoshiro, recommended to General Minami Jiro, the commander of the Guandong army, that Japan should treat the Jews well in order to attract their capital to Manchuria.
... General Higuchi Kiichiro, chief of Guandong army's Special Branc, and Colonel Yasue Norihiro, the army's specialist of Jewish Affairs. Higuchi and Yasue allowed thousands of Jewish refugees to settle in Manchuria, and for this the Jewish community of Harbin inscribed their names in the Golden Book of the Jewish National Fund in Jerusalem. The German ambassador to Japan, Eugen Ott, protested the actions of Higuchi and Yasue, but the Japanese government ignored his protests.
Other Jewish refugees arrived in Shanghai by boat from Europe. Until the outbreak of the Pacific war about twenty-five thousand refugees settled there, joining a local Jewish population of five thousand that included several wealthy families from the Middle East, such as the Sassoons and the Kadoories, as well as Russian Jews. After the attack on Pearl Harbor, the Japanese occupied the whole city of Shanghai. At that time the thirty thousand Jews in the city constituted the largest foreign group there and the largest Jewish community that had ever come under Japanese control. No more refugees were allowed into the city, but those already there were not harmed