The earliest written records in reference to the islands come in the form of a record of Chinese geography during the Song period of China c.a. 1200 CE titled Yudi Jisheng (舆地纪胜) written by Wang XiangZhi （王象之). The location of the Diaoyu Tai (钓鱼台) as being part of the compilation is listed as a famous location in the Chinese domain, and the naming related to a Chinese fishing myth. Unfortunately, Yudi Jisheng is a point of contention for several reasons: The location of the islands is not the same in the book as the Senkaku/Diaoyu island geographic location, and there is no reference to when the islands came to be referred to as Diaoyu. Also, the work itself went into disappearance for about 600 years until it was rediscovered in the early 1800s of the Qing dynasty and subsequently put into print in the mid 1800s.

That's about all I can answer for on the Chinese side, except to say that though it is also known that Chinese expeditions to Japan and around the East China Sea are known, no records exist documenting the encountering of the Diaoyu islands. Instead, most of the Chinese argument for sovereignty over the islands has come from Ming dynasty documents. I cannot speak to any expertise on the Japanese history or the history of the LiuQiu Kingdom in the area.

Source for most of this information: Sovereign Rights and Territorial Space in Sino-Japanese Relations: Irredentism and the Diaoyu/Senkaku Islands by Unryu Suganuma

A book, called "Chou hai tu bian" (筹海图编) published in 1561, shows that the Diaoyu Islands had been placed within China’s maritime defense system in the Ming Dynasty.

http://p4.img.cctvpic.com/program/china24/20120916/images/1347758884806_1347758884806_r.jpg

Additionally, several Japanese official maps made during the Edo Period in the 17th Century also marked them as Chinese territories with their individual original Chinese names.

Historically, the area was used as fishing ground by Chinese fishermen.