Unauthorised Chinese versions of the latest Harry Potter book have been sold in Beijing, three months before the official translation is published.
The English version of the Potter book was released in China in July
The English language version of Harry Potter and the Half-Blood Prince was released around the world on 16 July.
Sold for 20 Yuan (£1.40), the unofficial Chinese version was said to omit paragraphs and contain errors.
Thousands of fans have also posted their own German translations of the book onto an unofficial Potter website.
Author JK Rowling's boy wizard Harry Potter is wildly popular in China, where he is known as "Ha-li Bo-te".
Foreign companies say unofficial versions of goods such as books, movies and designer clothes cause them to lose billions of pounds in potential sales in China.
Published by People's Literature Publishing House in China, the official English-language hardcover Harry Potter books were sold in Beijing for the equivalent of £11.90.
The unofficial translation omitted several paragraphs of action and contained some mistranslations, such as swapping the original word "immortal" for "mortal".
In 2003, the Chinese publisher tried to thwart piracy by rushing out its translation of previous instalment, Harry Potter and the Order of the Phoenix, 10 days before its scheduled release.
A spokesman for Rowling's London agent, Christopher Little, said it had successfully taken action against Chinese pirates but declined to give further details.
Harry Potter is popular in China, where he is known as "Ha-li Bo-te"
Potter readers have posted their own international translations of the latest book onto fan websites, with thousands of German versions posted fewer than 48 hours after its English-language publication.
To avoid threats of legal action, fans pledged not to distribute their translations to any third parties.
On China's Tsinghua university website, a fan writing under the name Woodchuckle was so upset by Rowling's ending that he wrote and posted his own.
The university site administrator said it had deleted several postings which contained illegal electronic versions of the book.