A colleague of mine asked where I found my working definition for one, one-and-a-half and two-sided games that appears in some of my game design lecture material. As far as I know, there is no "official' lexicon for war gaming, so I made it up. In truth, it is not so much a definition of WHAT two-sided gaming is, but rather WHEN you should use two-sided vs. one or one-and-a-half sides in your game design. Perhaps the best way to think about sides in a war game is to take it from the players' perspective, i.e. "Who am I playing against and what is their objective?" and "What is the role of Control?"

If the challenges facing the player team (e.g. the Blue Team) are primarily created by a moderator, facilitator, faculty group or control team whose only purpose in the game is to poke, probe or otherwise stimulate Blue to think about and respond to a problem, often in a pre-scripted manner - in other words, have no gaming winning objective of their own - then it's a one sided game. If the adversary is a separate team from the control group, but under Control's close supervision in order to maintain game pace, direction and overall objective, then you have what we call a one-and-a-half sided game, the half being some aspects of a Red Team. Red in this case is essentially working for Control to assist in achieving the game's larger objective, which is often educational in nature. In this case Red is sometimes referred to as Pink (part White or control cell, part Red cell). In both these cases, Control or a notional Red is performing more of a Devil's Advocate or Anti-Blue role than a Pro-Red role for the purposes of challenging Blue.

If on the other hand, Red gets to play in a dynamic manner to achieve their own victory conditions, then you have a two-sided game (or multi-sided game). From either side's perspective, they are battling against another set of players on equal footing. Neither side has any undue or disproportionate interaction with Control. From an outside observer perspective, the sides are indistinguishable in terms of their purpose - that is, to win the game. Control acts more as an umpire to ensure the game is played according to the rules, and the score is the score.

You know you're probably NOT in a two-sided game:
- If injects are used or the game is MSEL driven.
- If the Red Team is being steered directly by Control.
- Phrases like "keeping Red in their box" are used.
- If Control, in acting as higher authority for both sides, is far more constraining and manipulative of Red than Blue.
- If Red winning runs counter to the game's objective.
- If there is no interest in whether or not Red can or does win.

Two-sided games are more psychologically demanding. Take for instance a computer based game that can be played solitaire (against the computer) or networked with another human opponent, which I have at home. When my son plays against the computer, the game "feels" one or maybe one-and-a-half sided. While he doesn't like to lose to the computer, contrast that against when he plays against his brother on the other computer. The game now is definitely two-sided and the emotional commitment to the outcome is quite a bit higher! As McCarty Little put it, "Now the great secret of its [war game's] power lies in the existence of the enemy, a live, vigorous enemy in the next room waiting feverishly to take advantage of any of our mistakes, ever ready to puncture any visionary scheme, to haul us down to earth." And if that applies to both sides, you have yourself a powerful two-sided game.