for reasons I don't really understand, Bai Chongxi of the Kuomintang is called by Taiwanese and mainlanders, 'Little Zhuge'.
At any rate, Mao Zedong is obviously the greatest strategist of the 20th century, and is likely the greatest in Chinese history. If you want to count strategists that invaded China, then I would put Genghis Khan above him, but no other.
Mao went from being a sullen teenager to being a bandit warlord to leading a revolutionary army, and his ideas on military operations are probably deeply influential in every civil war/ insurgency being carried out on this planet.
He escaped numerous attempts to destroy the PLA by the KMT, continued to weaken the KMT even while fighting the Japanese (while allowing the KMT to take the brunt of the war), and then managed to completely the rout the KMT. His armies prevented the UN from winning the Korean War. And he established a system of control over all of China which shows no signs of failing. So what if his domestic policy was absolute, complete disaster, the man knew how to make things go his way...
Mao, all the way.