On a serious note, Chimps did not evolve directly into humans. There were innumerable mutations in between. The Java man, Australopithecus, Lucy the Hominid, Neanderthals, and whole bunch of other species which branched off, evolved and eventually the modern man appeared some 100,000+ years ago.
Some species such as crocodiles & great white sharks did not evolve much in million years because they have little trouble surviving. Only the intelligent hominids could escape from being eaten by lions & tigers and with every generation the smarter ones were able to pass on the genes.
In other words, chimps accidentally changed into chess-masters, with some accidental steps in between.