Mochi ("Buffalo Calf"; c. 1841 – 1881) was a Southern Cheyenne woman of the Tse Tse Stus band and the wife of Chief Medicine Water. Mochi, then a 24-year-old, was a member of Black Kettle's camp and was present on the morning of November 29, 1864, when John Chivington and over 650 troops of the First Colorado Cavalry, Third Colorado Cavalry and a company of the 1st Regiment New Mexico Volunteer Cavalry attacked Black Kettle's winter camp at Sand Creek on the plains of eastern Colorado Territory (referred to as the Sand Creek Massacre).
During the unprovoked attack, Mochi witnessed her mother being shot in the forehead and killed by an American soldier who had entered their tipi. According to her account, he then attempted to rape her, prompting her to shoot and kill him with her grandfather's rifle. She then fled the camp with the other survivors trying to evade Chivington's men. After the massacre, she became a warrior and engaged in raiding and warfare for the next 11 years.
Mochi fought alongside her husband in numerous battles and raids and was the only Native American woman to be incarcerated by the United States Army as a prisoner of war.
On August 24, 1874, in present day Meade County, Kansas, Mochi, Medicine Water and the other members of their band were involved in the massacre of a surveying party led by Capt. Oliver Francis Short, who had fought in the Union Army during the American Civil War. Short, his 14-year-old son Truman, and four other members of the party were killed, with three of them being scalped.
On the morning of September 10, 1874, in Kansas, Chief Medicine Water and his band, including Mochi, attacked John German and his family as they were breaking camp. The family had camped along the stagecoach route which followed the Smoky Hill River while en route to Fort Wallace.