Qiu Xiaolong, a St. Louis-based novelist whose mystery thrillers are set in Shanghai, said Chinese publishers who bought the first three books in his Inspector Chen series altered the identity of pivotal characters and rewrote plot lines they deemed unflattering to the Communist Party. Most egregiously, he said, publishers insisted on removing any references to Shanghai, replacing it with an imaginary Chinese metropolis called H city because they thought an association with violent crime, albeit fictional, might tarnish the city’s image.