A House Divided is unquestionably my favorite game about the Slaveholder's Rebellion (better known to many as the American Civil War, and to Reb sympathizers as "The War Between the States," or in sad and extreme cases as "The War of Northern Aggression"). It deals with the entire war, barring minor actions in Texas, with a map whose four corners cover roughly New York, Kansas, Louisiana, and northern Florida. It's also playable in a few hours.
One of the reasons I like it is that, by the standards of board wargames, it is remarkably simple, with rules that should daunt no Eurogame player. I would describe it as "elegant," in the sense of providing a high quality of simulation value for a relatively sparse investment in complexity; indeed, of all of Frank Chadwick's many designs, it is the one I admire most highly.
First published in 1981, it is today available in a nicely produced edition from Phalanx Games, with additional set of "advanced" rules from Alan Emrich. I'm of two minds about those rules; while they provide some options and additional rules for those who have worked the changes on the essential game, they also muddy what's most attractive about the game as a whole, namely its clarity and simplicity.
As a game qua game, it is not without flaw: Essentially, if the Rebels are going to win, they are going to win quickly, because the superior population and industrial might of the legitimate government of the United States will ultimately overpower them. The rules do permit the South to win by delaying the inevitable longer than historical, but this makes the late game a grinding battle of slow advance by the Grand Army of the Republic, resisted with increasing desperation by the traitors of the South.
(Are my historical sympathies showing here? By Jove, I believe they are.)
A House Divided was one of the first games to use a point-to-point system, with game locations attached by lines, a mechanism for recreating paths without the need for an artificial grid. Each turn, the players roll to determine how many units each may move, which, given the larger number of Union units, neatly recreates the South's superior initiative and command structure without any great burden of complexity. Battles are a matter of lining up units in an area and rolling dice to "hit" opponents; one survivor on the winning side may be promoted to "Elite" status, which increases its abilities in combat, representing the rawness and lack of training of recent draftees and recruits. Rail links allow units virtually unlimited travel behind the lines, while Union but not Confederate units may move down rivers at double normal speed, representing Union riverine dominance, again without the need for any great complexity.
Strategies developed by the players tend to follow historical paths as well; the Rebel player is often tempted by an early strike toward Washington, while Union strategy is based on dividing the Confederacy, first along the Mississippi and then along other routes, while capturing as many recruiting centers as possible along the way.
Eurogame fans may find it too often dictated by luck at the dice, but as I've argued, a random element is essential in simulating the many uncontrollable factors of war; and the end-game can become a grind, particularly if it's fairly obvious that the South has no great hope of victory. But as both a simulation and a game, it succeeds, and with remarkable conciseness.