The unwritten rules of mainland corruption have just been written down, and they make interesting reading. If a senior official approves a project by signing his name vertically, it means 'do it straight away', whereas a horizontal signature says 'put it on the back burner'. A full stop after the signature means 'spare no effort on this project', while a circle indicates 'it's useless even if I sign it'. Lower-ranking officials have to learn the rule by themselves, and it's just one of many that have to be learned for a successful career in China's bureaucracy. Jiang Zongfu , a 41-year-old former vice-mayor of Linxiang , Hunan , has revealed the secrets of how to survive in mainland officialdom in his book My years as an official: an original record of my undercover life as a (county-level) vice-mayor. The 250,000-word book documents his experiences in five years as deputy chief of Linxiang, a county-level city under the jurisdiction of Yueyang , and uses the real names of Jiang's colleagues and superiors. He says the crux of survival as an official is to adapt to the hidden rules. 'To be an official is a high-risk career,' he said yesterday. 'You have limited power but enormous responsibility, and things are especially cruel for grass-roots-level officials.' He had to face all kinds of temptations, including money and lust, and 'had my heart in my mouth for five years'. Another secret he reveals is how officials avoid trouble after leaving a post. They give a red packet, containing money, to the local Discipline Inspection Commission, the Communist Party's anti-graft watchdog. The amount of the money given usually equals the largest bribe the official has received during his term in office. 'In this way one could avoid being investigated,' he said. Jiang, who describes himself as a 'secret agent' in the government, finished the book on August 8 and is negotiating with a publisher. He wrote it while in hospital for three months after being removed as vice-mayor. He said one of the reasons he wrote the book was to put the spotlight on Linxiang - a small, well-off city with a population of about 500,000 - and provide a reference for the nation's political reform. Jiang said he was not sure whether the book could pass the censorship process, adding 'it would be such a pity if it's banned'. He also said he feared revenge for telling the truth. Jiang, a former journalist, said his entry into officialdom was abnormal and more of an accident. He was made vice-mayor in 2005 because of an online posting he wrote while a civil servant. It took the form of a letter to the party secretary of Yueyang and suggested several ways to improve Yueyang's travel industry. His removal as vice-mayor this year was also related to his online postings, which caused headaches for his superiors in Linxiang. In a January posting, he lashed out at internationally acclaimed filmmaker Zhang Yimou , describing his Impression spectaculars as wasteful and repetitive. In April, he criticised surging home prices and accused economists of colluding with property developers. The postings might not have been too sensitive on their own, he said by phone yesterday, but they coincided with two safety incidents in the town of Taolin, near Linxiang - an explosion in January and a school poisoning in April. He said Linxiang's party secretary thought his postings had attracted many reporters and could lead to more coverage of the two incidents, tarnishing the city's image. Jiang was told in May he would be transferred to Yueyang to become an assistant dean at a college. He said the fundamental reason for his removal was his character - straightforward and candid - which was not suitable for an official. Jiang said he felt lucky that his time in officialdom had not changed him. In the early 1990s he worked as a journalist for a Yueyang newspaper, exposing many inside stories about the workings of government and ending up on the local authorities' watch list. He said he was looking forward to a new life in academia. 'In academia there should be more freedom of speech.'