In China's burgeoning art and antiquities auction market, there are many questions no one wants to answer.
Which government department, for instance, is selling one of the most famous official paintings of Mao? This goes under the hammer today in Peking, estimated to raise more than 1.8m yuan (pounds 140,000).
Where will Peking's cash-strapped Palace Museum find the money for its successful 18m yuan record bid on Thursday for the 1,000-year-old Song dynasty painting Pictures of Ten Poems by Zhang Xian?
And, in a market where a pair of early 18th-century carved wooden wardrobes is expected to raise at least 1.5m yuan, a Yuan dynasty ceramic pot is marked down at 2m yuan, and even modern oil paintings start at around 50,000 yuan, who are the mainlanders who can find this kind of money?
This week has seen auction fever in Peking. Three state-owned Chinese auction houses, Rong Bao, Hanhai and Guardian, have gathered some 2,800 artworks and antiquities valued at around 200m yuan for a series of auctions which continue over this weekend. In recent days, Christie's and Sotheby's have held their first exhibitions in Peking, to encourage mainland interest in collections of ceramics and jade jewellery from outside China which will be auctioned in Hong Kong at the end of this month.
And just two years after auctions of antiquities were first sanctioned by the state, the Chinese are certainly buying. In Hanhai's auction on Thursday, more than pounds 3m worth of paintings were sold, aside from the Palace Museum purchase, with mainlanders playing their part.
Julian Thompson, chairman of Sotheby's Asia, said there had been a ''tremendous upsurge'' in mainland purchasing over the past two to three years. According to Wang Yannan at the Guardian auction house, this year also has seen an increase in overseas sellers consigning pieces to China for auction, because of the buoyant market.
It is difficult to discover who these mainland buyers are, because with crackdowns in China against corruption and tax evasion, no one wants to admit to having large amounts of spare cash.
Just as mysterious are the sellers. The 1967 picture Chairman Mao Goes to Anyuan was the most famous painting of Mao to be released during the Cultural Revolution. The image of Mao striding across the hills was reproduced on stamps, badges and 900 million posters. Is the Chinese Communist Party now flogging off its propaganda heirlooms?
Ms Wang at Guardian said the majority of the paintings, ceramics, jewellery, rare books and furniture on offer at their auctions was being sold by mainland individuals who have woken up to the increased value of family treasures.
Up to 300 people are expected to register to bid at the Guardian market and, judging by experience, more than half the buyers will be mainland Chinese. Ms Wang identifies three types of mainland buyers. ''The first is corporations buying for the collection of the company. Then there are private individual collectors, and mainland art dealers. The buyers are mostly young and middle-aged, because these are the people who now have the money. A lot of them are in the stock market or real estate business,'' she said.
Lillian Chu of Christie's said: ''The history of collecting is in the Chinese blood.'' Christie's and Sotheby's both have representative offices in Shanghai and say that, at their top end of the market, there are about 10 mainlanders who take part in their auctions outside China.
''I believe that the trend is going to be that corporate art is going to start in China.'' She described the buying power as ''quite surprisingly strong''. In some cases prices have been higher inside China, particularly for paintings.
Chiang Lim-che, a Hong Kong furniture dealer, said most mainland Chinese buyers were looking for an investment. ''There are a lot of people buying in China,'' he said. ''They want to make money rather than own art. They pay attention to the value more than why something is a good piece, or the history of the piece. In China the most frequent question is 'How much is it worth?' ''