The Shanghai Ghetto, formally known as the Restricted Sector for Stateless Refugees, was an area of approximately one square mile in the Hongkew district of Japanese-occupied Shanghai (the ghetto was located in the southern Hongkou and southwestern Yangpu districts which formed part of the Shanghai International Settlement). The area included the community around the Ohel Moshe Synagogue. Shanghai was notable for a long period as the only place in the world that unconditionally offered refuge for Jews escaping from the Nazis. After the Japanese occupied all of Shanghai in 1941, the Japanese army forced about 23,000 of the city's Jewish refugees to be restricted or relocated to the Shanghai Ghetto from 1941 to 1945 by the Proclamation Concerning Restriction of Residence and Business of Stateless Refugees. It was one of the poorest and most crowded areas of the city. Local Jewish families and American Jewish charities aided them with shelter, food, and clothing. The Japanese authorities increasingly stepped up restrictions, surrounded the ghetto with barbed wire, and the local Chinese residents, whose living conditions were often as bad, did not leave. By 21 August 1941, the Japanese government closed Shanghai to Jewish immigration. Starting from 1934, one year after The Nazi Party gained control over Germany, some people chose China as a shutter for Jewish refugees. According to Gao Bei, a history professor from the University of Charleston, three plans were listed as the following: Maurice William, a Russian Jewish dentist who lived in New York, was the first one to suggest that China could be a shelter for Jewish refugees. William first showed his plan to Albert Einstein, who was recorded as being impressed by this plan. Later, William sent his plan to China for approval. However, the proposal was likely declined at that time. One possible reason for this may have been that China did not want to stand in opposition to Germany.