Factual error: There is a three prong electrical outlet visible in the Wershba's bathroom. These were not used at the time the film takes place, they were introduced decades later.
Plot hole: The movie takes place before and around 1938 and, supposedly ends in that year, following the entrance in Shanghai of the Japanese, with the exodus by many Chinese and foreign residents. Ralph Fiennes' character, as an American ex-diplomat and businessman, would have resided, have bank accounts, his car, etcetera, in the foreign concessions. The Japanese did not occupy the concessions until after Pearl Harbor, so there was no need for him to flee the city, as a refugee without a passport and with little or no money, sailing towards Macao in a fragile Chinese junk. He could just have driven or walked a few blocks to any of the "Western" concessions, from where he could have married Natasha Richardson's character, obtained U.S. passports (White Russians had none, as the rest of her family in the movie until assisted by an official in the French Consulate) for her and her daughter, purchased a ticket in a safer vessel, sold his assets (regardless of the damage to his club, he still had a house, furniture, a car, presumably bank accounts, etc.).
Other mistake: When the USA soccer world cup team is practicing in New York, on some field in Long Island, in several shots you can see the steeple for Union Avenue Christian Church, which is actually located in Saint Louis, Missouri.
Factual error: In an early scene, a character suggests that a man might be awarded an OBE honor if he wins the 1913 US Open. The OBE wasn't established until 1917.