外蒙在宣統三年（1911）脫離清帝國後，欲建立一統全蒙古的政權。受此影響，民國未及接管的內蒙牧廠、喇嘛廟紛紛外附，成為外蒙的軍事基地與聯絡網。外蒙遂依靠俄國幫助，以內蒙將領為先導，在1912年10月25日南下內蒙、1913年春西進阿爾泰。戰爭席捲北部邊疆，造成民國與外蒙政權的最大衝突。北京政府冊封內蒙章嘉、甘珠爾瓦兩位活佛以削弱外蒙教權影響，封禁內蒙糧運以遏制外蒙軍隊南下，並針對蒙軍戰術缺陷實施「跳廟作戰」，逐一拔除據點。1913年夏，熊希齡、馬福祥翦除外蒙南下內蒙的東、西兩路，將蒙軍限制在中路；楊增新、帕勒塔阻止外蒙西進阿爾泰。此時南方二次革命突發，外蒙趁機擴大戰爭動員，北京政府優勢頓挫。二次革命結束後，北京政府密促蒙軍中的內蒙將領歸附，又統籌陸軍第一師、毅軍、奉軍等不同區域兵團聯合作戰，扭轉內蒙中路戰局，迫使俄國督促外蒙撤軍。1913年末，北京政府與庫倫當局劃定停戰線，其南段使內外蒙之間的地方性旗界上升為國家軍事防禦線，其西段則切開阿爾泰烏梁海、新和碩特、新土爾扈特各部，改變清朝以部落地域為邊的傳統，影響日後的中蒙兩國分界位置。

Upon declaring independence from the Qing Empire in 1911, Outer Mongolian leaders strived to establish a pan-Mongolian regime. Following the 1911 Revolution, the failure of the nascent Chinese Republic to establish effective control over several lama temples in Inner Mongolia freed those temples to align themselves with Outer Mongolia. In turn, this gave Outer Mongolia a launch pad for invading Inner Mongolia and for building ties with pro-independence and pan-Mongolian groups in Inner Mongolia. Relying on Russian support, the Outer Mongolian advance was spearheaded by several turncoat generals from Inner Mongolia. After invading Inner Mongolia on 25 October 1912, the Outer Mongolian forces then advanced westwards into the Altai region in the spring of 1913 and took advantage of the unrest during the Second Revolution to launch an even greater offensive, engulfing the entire northern frontier in the flames of war, leading to the most intense conflict between the Republic of China and the authorities of Outer Mongolia. The Beijing government bestowed official titles upon the two living Buddhas to weaken the Outer Mongolians’ religious influence over the local population, and capitalized on the Outer Mongolians’ logistical weaknesses to thwart their advance. At the same time, the Beijing government responded to the “nomadic tactics” of the Outer Mongolians by “temple hopping,” which allowed them to recapture much territory. In the summer of 1913, Xiong Xiling and Ma Fuxiang annihilated the left and right wings of the Mongolian forces advancing southward, while Yang Zengxin and Palta repulsed their westward thrust. Consequently, only the Mongolian force in the center (i.e., directly facing inner Mongolia) remained intact. When the Second Revolution broke out in the south, Outer Mongolia capitalized on this opportunity to renew its mobilization efforts, then proceeded to negate the erstwhile advantage enjoyed by the Beijing government. After the Second Revolution ended, the Beijing government successfully won over several Inner Mongolian generals and convinced them to switch sides. Moreover, the Beijing government turned the tide of the war in its favor by coordinating maneuvers by various units across military zones in the north, eventually forcing the Russians to pressure the Outer Mongolians into withdrawing their troops. In late 1913, the Beijing government and the Kuriye authorities signed an armistice along the line of actual control. Along the southern sector of that line, the border between local banners was transformed into a defensive line garrisoned by the troops of two opposing nation states; the western sector bisected the traditional territories of tribes in the Altai region, thereby changing the previous practice under the Qing of drawing national boundaries according the territories of tribes. To a certain extent, this set the China-Mongolia border ever since.

熊希齡; 袁世凱; 辛亥革命; 北京政府; 外蒙古

Xiong Xi-lin; Yuan Shih-kai; the Revolution of 1911; the Beijing Government; the Outer Mongolia