SINCE it was first printed in 1610, China’s most famous or notorious erotic novel “Jin Ping Mei” (“The Plum in the Golden Vase”) has been labeled pornographic and corrupt and officially banned over the years.

Of course, it was surreptitiously read by the educated classes. Today it’s more like your grandfather’s porn, since other, much more sexually explicit material is widely available.

After years of being read under the bed covers, “Jin Ping Mei” today is regarded as a masterwork of Chinese and world fiction, a landmark in the development of the novel and powerful social commentary about a corrupt society. Still, there are blushes over its graphic sexual depictions and only one of many Chinese professors recently interviewed admitted to having read it. It is not taught in literature classes, though it is listed as one of the classics.

Last year, after more than 30 years’ labor, American professor emeritus David Tod Roy of the University of Chicago completed his five-volume translation with more than 4,400 footnotes. It was a major event in translation and publishing.

It was hailed as an epic scholarly achievement and the first complete European-language translation of the epic and intricate Ming Dynasty (1368-1644) novel of manners.

It is not available in China, and it is not known whether it will be imported. One Chinese reader found Roy’s translation a much smoother, easier and more interesting read than the vernacular Chinese.

The translation took more than 10 years; the first volume was published in 1993. The footnotes alone are an awesome achievement.

“Roy’s translation and its annotation aim to faithfully represent and elucidate all the rhetorical features of the original in its most authentic form and thereby enable the Western readers to appreciate this Chinese masterpiece at its true worth,” said the Princeton University Press.

Controversial doesn’t begin to describe the novel written in the vernacular, which created a sensation akin to that of “Fanny Hill” (1749) and “Lady Chatterley’s Lover” (1928).

Roy, 80, has said the only novels of comparable quality are “The Tale of Genji” (1010) and “Don Quixote” (1615).

“‘Jin Ping Mei’ does not resemble either of these, but it is an equally sophisticated work of prose fiction with many, many features that are unprecedented in previous Chinese and world literature,” Roy told a workshop last fall in the University of Chicago.

The book contains 900 passages of poetry, parallel prose and proverbial sayings. There are around 800 men, women and children from all classes of Chinese society down to servants, street hawkers and singing girls. There are rich descriptions of food, clothing, household customs, medicine, games and funeral rituals.

And there is sex. In the course of the novel, protagonist Ximen Qing has 19 sexual partners, including six wives and mistresses. They enjoy 72 encounters in a variety of situations.

The novel is also a study of the simple mechanics of corruption, and it gives exact prices for just about everything, such as how to buy off a salt official. It’s all there.

“It’s an extraordinarily detailed description of a morally derelict and corrupt society,” Roy said.

The book, which first circulated in hand-written versions, was written by an anonymous author using the pen name Lanling Xiaoxiao Sheng, or the Scoffing Scholar of Lanling.

Framed as a spin-off from “Water Margin,” another Ming masterwork, “Jin Ping Mei” draws its two major characters, Ximen Qing and one of his wives, Pan Jinlian, from “Water Margin.” In the first chapter, Ximen murders Pan’s husband and takes her as a wife.

The novel then follows the domestic sexual intrigue among women in his household as they struggle for prestige and influence at a time when the corrupt Ximen clan is declining.

In the end, Ximen dies from an overdose of aphrodisiacs administered by Pan to keep him aroused.

“A book of manners for the debauched. Its readers in the late Ming period likely hid it under their bed covers,” said Amy Tan, a Chinese-American author best known for “The Joy Luck Club.”

Roy was born in 1933 in Nanjing, capital of Jiangsu Province. Both of his parents were Presbyterian missionaries.

As a boy, he spoke fairly fluent Chinese, but he could neither read nor write. In 1949-50 when there were no Western schools in Nanjing,

Roy was taught Chinese at home by a professional tutor.

“I became totally obsessed with the language ... by the end of the year I could actually read a Chinese newspaper,” Roy told graduate students at a workshop in the University of Chicago.

He steeped himself in the Chinese classics: “Romance of the Three Kingdoms,” “Water Margin,” “Journey to the West,” “Dream of the Red Mansion” and “Jin Ping Mei.”

In 1950, he found an unexpurgated version of the novel in a second-hand shop. At that time many people threw away books that were dangerous to own. “But I was a teenager so I was excited by the prospect of trying to read something pornographic,” Roy recalled.

From 1950, he devoted his studies to “Jin Ping Mei.”

He spent two years making index cards of every line of poetry, parallel prose and proverbs in the novel. He tried to read every work of Chinese fiction and drama in circulation before “Jin Ping Mei” was published.

“It was huge work, but it felt great,” Roy said, “mainly because I could thumb my nose at the people who said I would never finish.”

Around the same time he completed the work, he was diagnosed with ALS, also known as Lou Gehrig’s disease. “So I associate my accomplishment ... with my decline,” he said.

Canadian novelist Stephen Marche called “Jin Ping Mei” a “mean-spirited page-turner.” He cited the legend that it was written to avenge the murder of the writer’s father.

The author supposedly sent the manuscript, with poison rubbed into the corners of pages, to the murderer. The victim was riveted by the tale, couldn’t put it down, and died after completing the book in a single sitting.

Tan Chung, professor emeritus of Chinese Literature at the University of Delhi, who now lives in Chicago, called it a profound work but said the pornographic details eclipse other descriptions of eating, costumes, political corruption, funerals, and so on. “I would suggest you read literature that promotes the zhen (truth), shan (goodness) and mei (beauty),” he said.