Location of Kiau Chao on the Shandong Peninsula.
The area of Tsingtao was hardly populated when the Chinese Empire established a naval stronghold there in 1891. This was noted by the Germans, who wished to claim their own trading hub on the Chinese mainland after the British had succesfully established Hong Kong after the Opium Wars in the 1840's. In 1897 the German Navy captured the Chinese stronghold and a year later agreed to lease an area of around 500 square kilometers from which to organise German commercial interests in China. The Germans invested heavily in Tsingtao, and it achieved very high living standards (for Chinese standards at that time) in a matter of years. The Tsingtao beer brewery, which produces the well-known brand, dates from this particular era in history.
At the start of WW1 in 1914 Japan issued an ultimatum demanding Kiau Chao from the German Empire. It was captured quickly after. In 1922 the Japanese handed it to the Republic of China only to annex the territory again during the Sino-Japanese War of 1937. In 1945 it reverted to China. The last decades the city of Qingdao has developed into a modern metropolis and important harbour and financial center. There a still a few landmarks that remind of the German presence that lasted only 16 years.
Currency
Initially, Kiau Chao used the same money as what was used in the Chinese Empire. These were mainly silver coins, either Spanish/Mexican Dollars or Chinese Yuan or Taels. From 1907 the German-Asian Bank issued a separate Kiautschou Dollar, which was equal to the Chinese Yuan and divided in 100 Cents. At that time, the Yuan was roughly equal to the US Dollar and worth approximately 4.20 Goldmark.
Stamp from Kiau Chao
In 1909 coins of 5 and 10 Cents were put in circulation. A new series of banknotes was issued in 1914, this time with denominations in Dollars as well as Taels. A Dollar was worth 0.72 Tael.
https://en.numista.com/catalogue/kiau-chau-1.html