On August 13, China’s official Xinhua News Agency reported on a document ostensibly from the State Administration of Taxation that explained new personal income tax rules in China. Gearing up to parse the document — “State Council State Administration of Taxation, Notice 47, 2011” (国家税务总局公告2011年第47号公告) — Xinhua asked: “So how are the old tax rules and the new tax rules connected? On [August 13], the State Administration of Taxation accepted an interview with our reporter. . . ”

The same day, Guangzhou Daily, the official party-run newspaper in the southern city of Guangzhou, was the first major print publication to run a report on the “new rules,” offering a detailed explanation.

Well, that official document, it turns out, was fake.

That’s right. An official government policy release, and it was apparently completely fabricated, though no one bothered to check. The State Administration of Taxation stepped out yesterday and officially said so, leaving many state media red-faced with embarrassment.

So where did Document No. 47 come from? That is now under investigation, authorities say. But in a report on the front page of today’s The Beijing News newspaper, Yue Shumin (岳树民), a professor of finance at People’s University of China, remarked the expertise with which the counterfeit official notice was made. “Looking at the text of the fabricated notice, it’s clear it is done with a definite level of expertise. If the fabricator didn’t have a good command of finance and taxation it would have been difficult to mislead the media and the public in this way,” said Yue.

Government authorities — yes, real ones — have stated their determination to hold those responsible to account. But beyond the question of who, there lingers the great big question of HOW.

Exposing its own mouthpiece reflex, the official Xinhua News Agency didn’t just report the fake notice as news — it claimed to have interviewed the “relevant responsible person” in the notice. This is typical of the way state media routinely take hand-off official releases from Party and government organs and repack them as reported news.

Here is the official China Central Television reporting the “news” of Notice 47 on August 14, complete with graphics calculating how the new policies will impact the average Joe. They even go out on into the city to interview the Man-on-the-Street about the new rules. So at least they did their footwork, right?

The timing of these revelations could hardly be more interesting. Over the past two weeks a debate has simmered in China over the issue of “rumors” on social media and the question of the truth and credibility of information.

Much of the chatter has centered on the so-called “anti-rumor league,” or piyao lianmeng, a group of online rumor busters who have advertised themselves as truth-seeking vigilantes out to identify and neutralize untruths in China’s burgeoning microblog sphere. The group’s crusade was trumpeted by state media. On August 3, China Central Television’s “Morning News” program reported under the title “Where is the ethical bottom line on microblogs?” the story of how one user on QQ Microblog called “Guo Yao” (郭瑶) had impersonated the relative of a July 23 crash victim.

But critics pointed out justifiably that the “anti-rumor league” focused excessively on popular rumor, turning a blind eye to misinformation by the government. Many harbored a suspicion that the League and the whole attack on microblog rumors was an attempt black-wash social media as a problem, particularly in the wake of the furor over the handling of the July 23 Wenzhou train collision, in which microblogs played a crucial role. Others pointed out that the real root of rumor and misinformation is the government’s own policies of news and information control.

Look, then, at the way commercial media today have pounced on the story of Notice 47, drawing it into the larger debate over rumor and truth. Here is today’s Southern Metropolis Daily newspaper. The large bold headline across the top, above the image of Hu Jintao visiting Guangzhou, reads: “Premium Allocation Tax Assessment? It’s Fake! The State Administration of Taxation Document Was Fabricated.”

And here is the front page of Morning News, a commercial spin-off of the official Sichuan Daily, which reads across the top, “Anti-Rumor Announcement,” or piyao shengming (辟谣声明). The big black characters read, “This is fake,” referring of course to the widely disseminated Notice 47. But for any reader savvy enough to have followed the recent debate over “rumor,” the words piyao (or “rumor-busting”) in the headline will almost surely recall the ethical attack on social media.

Clearly, rumor and fabrication are not issues confined to social media. And this particular revelation of rumor is probably something the “anti-rumor league” never saw coming.