chiu_ is SHACHAU, "Sand-district," an outpost of China Proper, at the
eastern verge of the worst part of the Sandy Desert. It is recorded to
have been fortified in the 1st century as a barrier against the Hiongnu.

[The name of Shachau dates from A.D. 622, when it was founded by the first
emperor of the T'ang Dynasty. Formerly, Shachau was one of the Chinese
colonies established by the Han, at the expense of the Hiongnu; it was
called T'ung hoang (B.C. 111), a name still given to Shachau; the other
colonies were Kiu-kaan (Suhchau, B.C. 121) and Chang-ye (Kanchau, B.C.
111). (See _Bretschneider, Med. Res._ II. 18.)

"Sha-chow, the present _Tun-hwang-hien_ (a few _li_ east of the ancient
town).... In 1820, or about that time, an attempt was made to re-establish
the ancient direct way between Sha-chow and Khotan. With this object in
view, an exploring party of ten men was sent from Khotan towards Sha-chow;
this party wandered in the desert over a month, and found neither
dwellings nor roads, but pastures and water everywhere. M. Polo omits to
mention a remarkable place at Sha-chow, a sandy hillock (a short distance
south of this town) known under the name of _Ming-sha shan_--the 'rumbling
sandhill.' The sand, in rolling down the hill, produces a particular
sound, similar to that of distant thunder. In M. Polo's time (1292),
Khubilai removed the inhabitants of Sha-chow to the interior of China;
fearing, probably, the aggression of the seditious princes; and his
successor, in 1303, placed there a garrison of ten thousand men."
(_Palladius_, l.c. p. 5.)

"Sha-chau is one of the best oases of Central Asia. It is situated at the
foot of the Nan-shan range, at a height of 3700 feet above the sea, and
occupies an area of about 200 square miles, the whole of which is thickly
inhabited by Chinese. Sha-chau is interesting as the meeting-place of
three expeditions started independently from Russia, India, and China.
Just two months before Prjevalsky reached this town, it was visited by
Count Szechenyi [April, 1879], and eighteen months afterwards Pundit A-k,
whose report of it agrees fairly well with that of our traveller, also
stayed here. Both Prejevalsky and Szechenyi remark on some curious caves
in a valley near Sha-chau containing Buddhistic clay idols.[1] These caves
were in Marco Polo's time the resort of numerous worshippers, and are said
to date back to the Han Dynasty." (_Prejevalsky's Journeys_ ... by E.
Delmar Morgan, _P