“Zero-sum” is when one’s needs cancel out another’s needs.  I learned the meaning of this violent doctrine as a Russian kid playing “nozhichki.”  Nozhichki (“little knives”) is a game of divide-and-conquer.  First, with the point of your pocketknife you draw a sizable circle on hard ground.  Then, you divide it in half – one side for you, the other side is for your playing opponent.  Then you take turns flinging the knife into your opponent’s turf: if the knife “stands” (i.e. if the blade jams into the ground), then, following the line of the blade, you carve out a piece of your enemy’s territory and add it to your own domain.  And you continue the onslaught like this until you win over the entire circle or your knife falls flat, in which case it’s your enemy’s turn.  Either my pocketknife needed a better blade or my throwing hand wasn’t good or the ground in the Arbat neighborhood of Moscow (just a block away from the Spaso-House, the residence of the U.S. ambassador to U.S.S.R.) was too hard, but the games would often find me on the losing side.