War is not chess

  "Furthermore, war is not chess; one's opponent is not always playing by the same rules, and is often, in the effort to win, attempting to change what rules there are."

What interests Clausewitz, I argue, is not so much either pole in any of his analytical pairs, nor even either opponent in war, but the tangled dynamics occurring between them. This is consistent with the wrestlers' image of the Zweikampf. Many theorists tend, for the sake of analytical simplicity, to force war into the model sequence of move-countermove. But any good commander will seek to take advantage of the disproportionate effects or unpredictable situations generated by nonlinearities. Furthermore, war is not chess; one's opponent is not always playing by the same rules, and is often, in the effort to win, attempting to change what rules there are. This is a major reason that how war is conducted can and does change its character, and that any war is (in Maxwell's sense) structurally unstable.

Capturing the essence of this "true chameleon" is Clausewitz's aim. He is therefore willing to accept uncertainty and complex interaction as major factors in order to cope with what is happening along the hazy boundaries where the opposing forces in war, or contending categories in theory, are actually engaged. Facing up to the intrinsic presence of chance, complexity, and ambiguity in war is imperative. For Clausewitz, this is preferable to the risk of being blind-sided by the strictures of a theory artificially imposed on the messiness of reality in the name of clarity.

Unpredictability From Interaction,  Alan Beyerchen, "Clausewitz, Nonlinearity and the Unpredictability of War,"