Maoism is an adaptation of Marxist-Leninism. In Mao's case he adapted a theory that was originally developed within the context of a relatively advanced industrializing society, Europe of the 19th century, to a context of an almost purely aggricultural society--China of the early and mid 20th century.
Mao was a military genious, if not a political one, for his development of a protracted 'peoples war.' Whether you like him or not, and there is a lot not to like, his military theory was victorious and continues to be emulated today as well as studied by the students of West Point etc.
The Sandinista guerillas, though not self identified as Maoists, certainly practiced Maoism in their struggle against the Samoza regime in Nicaragua in the 1970s.