Playing wargames solitaire is by far the favorite mode. The most common reasons for playing solitaire are lack of an opponent or preference to play without an opponent, so that the player may exercise his own ideas about how either side in the game should be played without interference from another player. Wargames are, to a very large extent, a means of conducting historical experiments. So another player just gets in the way most times. For those players who do like to play with opponents, solitaire play is valued as a means of perfecting tactics and techniques in a particular game that will enhance the chances of success.
There are any number of techniques, which I'll get into later, for making a game a true solitaire game. Such a game is one in which an opponent is simulated by the game rules. But by far the easiest and most rewarding approach to playing a two player game solitaire is to simply play each side as if it was the only side you were playing. This is not as difficult as it sounds. Granted there will be some bias but the bias will not be as great as you might think. Each turn you simply either turn the map around and play the other side or go to the other side of the table or simply place the map so that you're in between either side's forces and move accordingly. It is sometimes interesting to either go to the other side of the table or simply move the map around so that you are behind the forces that you are playing. It changes the perspective on the game considerably. Simple things such as this will provide you with a rather rewarding solitaire game.
For those of you who care to do a bit more work there is another approach that requires more work, but has had its proponents over the
years. In this method you sit down with the game and analyze the situation each side faced with, and prepare a plan. This plan organizes each side's forces into half a dozen or so larger organizations. In other words, say in a game one side had 40 playing pieces on the map, each representing a battalion. The player would organize these battalions into divisions of five or six battalions each. The organization should follow whatever logic the battalion's deployment on or entry onto the battlefield dictated. Then, consulting the victory conditions and the number of turns in the game, the player would set up a timetable of what he felt reasonable goals should be for each of these divisions. He would also set loss levels at which the plans for these divisions would have to be changed. The same technique would then be applied to the forces on the other side. These plans would then be executed by the player who would simply be operating at a lower level than the theoretical commander of each army. This is merely a more formal, and to some people probably more comfortable, approach to my method of simply turning the map around and playing the other side.
There is no mystery in playing solitaire. Most players do it and many of them do it to a rather rewarding degree, simply by not getting wrapped up in any emotional desire for one side or the other to win. It is probably true that the older gamer has an easier time doing this, but then there's "comfort" to be taken in the fact that we all grow older and perhaps this happens a little more quickly for people who play wargames.