(The post was on the left (north) bank of the river, lost to the Russians in 1860.) According to the 18th- and early-20th-century European sources, and the reports of the Russians in the 1850s, the farthest Qing "advance guard" post was at Ulusu-Modon (Ulussu-Mudan) ( Chinese: 乌鲁苏穆丹 Wūlǔsūmùdān), near the Amur River's famous S-shaped meander. Little Qing Military presence existed north of Aigun. An additional advantage of Qiqihar may have been its location at the junction of a northbound road (to Nenjiang) and a westbound one (to Mongolia), enabling its garrison to defend both against the Russians and the Ölöt Mongols. According to modern historians, the moves may have been driven by supply considerations: Nenjiang and Qiqihar are connected by a convenient waterway (Nen River) with southern Manchuria, whereas accessing Aigun (Heihe) would require either sailing all the way down the Sungari River until its confluence with the Amur and then up the Amur to Heihe, or using a portage over the Lesser Xing'an Mountains between the Nen River valley and the Amur valley. However, already in 1690 the seat of the governor was transferred to Nenjiang (Mergen) on the Nen River, and, in 1699, further south to Qiqihar. The original seat of the Military Governor of Heilongjiang, as established in 1683, was in Heilongjiang City (also known as Aigun or Heihe, or, in Manchu, Saghalien Ula), located on the Amur River. Seal of the Guard General of Heilongjiang at the Heilongjiang General Mansion It is formerly romanized as "Heilungkiang". The standard one-character abbreviation for the province is 黑 ( pinyin: Hēi). Among the Altaic languages, the Manchu name of the region is Sahaliyan ula (literally, "Black River"), from which the name of Sakhalin is derived, while the Mongolian name with the same meaning is Qaramörin. Linguists suggested Hei ultimately comes from Qara/Hara/Har, a common Altaic language cognate meaning "black". Heilongjiang literally means Black Dragon River, which is the Mandarin name for the river better known by its Western name, the Amur River.