Dropa stones
Each stone disk was reportedly inscribed with two fine grooves spiraling from the edge to a hole in the disk's center (perhaps not unlike the Phaistos Disk). The disks were labeled along with other finds of the expedition and stored away at Beijing University for 20 years, during which deciphering attempts were unsuccessful.
When the disks were closely examined by Dr. Tsum Um Nui of Beijing around 1958, he concluded that each groove actually consisted of a series of tiny hieroglyphs of unknown pattern and origin. The rows of hieroglyphics were so small that a magnifying glass was needed to see them clearly. Many of the hieroglyphics had been worn away by erosion. When Dr. Tsum deciphered the symbols, they told the story of the crash-landing of the Dropa spaceship and the killing of most of the survivors by local people.
According to Tsum Um Nui, one of the lines of the hieroglyphs reads, "The Dropas came down from the clouds in their aircraft. Our men, women and children hid in the caves ten times before sunrise. When at last they understood the sign language of the Dropas, they realized that the newcomers had peaceful intentions . . . ." Another section expresses "regret" by the Ham that the aliens' craft had crash-landed in such a remote and inaccessible mountain range and that there had been no way to building a new one to enable the Dropas to return to their own planet.
Dr. Tsum's report supposedly appeared in a professional journal in 1962. He was subsequently ridiculed to the point of self-imposed exile in Japan, where he died. The Peking Academy of Pre-history never allowed him to publish and never speak of his findings.
"Tsum Um Nui" is not a real Chinese name, and critics suggest that Dr. Tsum may not have actually existed. However Tsum Um Nui is a Japanese name adapted to Chinese language. There is no evidence of him beyond the Dropa allegations.
Further research
In 1965, Professor Chi Pu Tei and four of his colleagues were finally given permission to reveal their theory. They published it under the title "The Grooved Script concerning Space-ships which, as recorded on the Discs, landed on Earth 12,000 years ago".
The records — some 716 grooved discs later uncovered in the same caves — tell an astonishing story of a space probe sent by the inhabitants of another planet. After landing at the Bayan-Kara-Ula mountain range, the scripts allegedly say, the peaceful intentions of the aliens confused the members of the Ham tribe, inhabitants of the neighboring caves, who hunted down and killed the extraterrestrials.
Photos claiming to show Dropa Disks are in fact Bi Disks, thousands of which have been found throughout China, mostly in the Southeastern Provinces. Bi Disks range in size of a few inches to several feet, and are most commonly made of jade or nephrite, with a round or square small central hole. Most Bi Disks date to the Neolithic Period (c. 3000 BCE), but are found up to the Shang Dynasty Period. Bi Disks beyond the Shang Period are usually more ornate, carved with dragons, snakes and sometimes fish, and used in ritual ceremonies. Most Neolithic Bi Disks were found in gravesites, buried beneath the head or feet of the deceased. It is theorised that this was to assist the deceased's spirit. No Bi Disks have been found to contain writing or spiral grooves as described in the Dropa story by authors such as Hartwig Hausdorf.
The Dropa Disks are said to be only 12 inches in diameter. However, one black and white photograph claimed by Hausdorf and others to display a Dropa Disk clearly shows the disk resting on a seat, and it is clearly several feet in diameter and has no markings whatsoever.