losses. This use of siege weapons was one of the first recorded uses of artillery bombardments against the enemy army to disrupt their resistance while simultaneously attacking them. In execution, his usage functioned more akin to the creeping barrage of World War I, used to soften and disrupt enemy lines right before an attack. Like Genghis Khan, Subutai was a master at creating divisions within the enemy ranks and surprising them. The terrifying Mongol reputation, combined with highly effective spy networks that spread discord, as well as incentives to key local leaders, prevented his opponents from effectively uniting and fighting at their full capacity. Central Asian campaigns (1217–1220) In 1217, Genghis Khan sent Subutai to hunt down the hated Merkits and their allies, the Cuman-Kipchak confederation, in modern-day central Kazakhstan. Subutai defeated them on the Chu River in 1217 and again in 1219 in Wild Kipchak territory. Before the battle of the Chem River in 1219, Subutai had his vanguard carry children's toys and leave them behind, as if they were a group of families fleeing from the Merkit. As a result of this deception, Subutai's army was able to surprise, encircle, and capture of all the Merkit/Kipchak leadership. Mohammed II of Khwarizm attacked Subutai shortly afterwards along the Irghiz River. Despite being outnumbered three to one against the Sultan's elite forces which had conquered much of Central Asia, Subutai held him off after a fierce battle and retreated during the night. According to Persian sources, this battle seems to have eroded Mohammed's confidence in his ability to defeat the Mongols in pitched battle, since Subutai only commanded a small 20,000 man force and did not want to even fight him. Supposedly the Mongol army had destroyed his left wing, and nearly broken his center and captured him, until reinforcements from his son arrived and the battlefield turned dark. Because of this battle, Mohammed was unable to take advantage of the upheaval in the Kara-Khitai Empire (simultaneously being conquered by the Mongolian general Jebe), like he had in earlier wars. Genghis Khan led the Mongol army westwards in late 1219 to invade Khwarizm as retaliation for the execution of Mongol ambassadors. With roughly 100,000 armed men, the Mongol army was numerically superior to the forces of the Khwarizim Empire, and through deception and rapid maneuver, the Mongols defeated the isolated Khwarezm armies in detail before they could react. Serving as