In recent decades, a series of inscribed graphs and pictures have been found at Neolithic sites in China, including Jiahu (c. 6500 BC), Dadiwan and Damaidi from the 6th millennium BC, and Banpo (5th millennium BC). Often these finds are accompanied by media reports that push back the purported beginnings of Chinese writing by thousands of years. However, because these marks occur singly, without any implied context, and are made crudely and simply, Qiu Xigui concluded that "we do not have any basis for stating that these constituted writing nor is there reason to conclude that they were ancestral to Shang dynasty Chinese characters." They do however demonstrate a history of sign use in the Yellow River valley during the Neolithic through to the Shang period.