I'm playing a game against Athena (the AI), as the North. Vanilla game, no mods. AI settings are Medium detection bonus, Hard difficulty, Normal aggressiveness, use all behaviors and give AI more time, and Hard-level activation bonus. It is June 1862.
The AI's behavior has been puzzling in several areas.
1) It has built very few (possibly no) ocean-going ships.
The CSA has sunk fewer than five and possibly only one Union merchantmen in the shipping lanes so far, and there haven't been *any* raiders or blockade runners visible (or even any messages about their activities) for several months now.
2) As reported by other players on this forum, it has a madcap lust for chasing after Union VP cities far to the north.
I reinforced Harrisburg and Pittsburg PA and Wheeling WV early and the AI left them alone, but it sent 7500 men to take Chicago IL and then Milwaukee WI late last year, and has just recently sent Jackson and roughly 35,000 man to take Cleveland OH. Boy was that a surprise! By comparison, there cannot be more than 45,000 men barring my conquest of all of northern Virginia, including Richmond. Only "house rules" have held me back.
3) Most puzzling of all - and something I very much hope other players can help me out with - is the AI's astonishing ability to support forces far from friendly sources of supply.
I mentioned an attack on Chicago and Milwaukee. The fact that a Southern army managed to get to Chicago healthy and battle-ready in wintertime harsh weather is interesting enough. In another game, I lost Lyon and his entire army (including both supply trains) in the same conditions after an overland advance of only four regions. What totally baffles me is that the southern army holed up in Miwaukee, was besieged, fought off three assaults, and was STILL reasonably healthy and battle-ready for the fourth.
But this is far from being the most astonishing feat of Southern logistics. Jackson walked through MOUNTAINS to get to Cleveland. Didn't take a single depot on the way. Paid no attention to maintaing a supply line or rail link. Lost both Winchester and Harper's Ferry to the Union. Arrives at Cleveland at least nine and possibly eleven regions away from the nearest Southern source of supply with a full corps at "green" readiness and sacks Cleveland. I don't understand. I would love to understand.
Early in the war, I destroyed both depots in south-central Missouri and assured myself that the Rebs would not be able to march anything overland capable of capturing cities held by four militia and one artillery battalion. Boy, was I wrong! I expected the cavalry raids. I didn't expect to see the enemy cavalry move furiously about and yet stay at "green" readiness deep in my territory (I'm talkin' IOWA deep here) while my countering cavalry forces rapidly lost cohesion and often strength as well. I have to retreat to the nearest source of supply, wait for my cohesion to come back (and often also replace the attrition losses), and try the attack again on some rebel force that is obligingly sitting still and forget about the one I was trying to chase.
I did not expect division-sized forces marching north through inland Missouri in winter while building not a single depot. I did not expect lone cavalry units to outfight small division-sized cavalry counterforces, even near my own cities and inside my own controlled regions, because they maintained cohesion and were supplied and I suddenly didn't have none of that. I did not expect army-sized forces to cruise up the Mississippi right on past the cannon of Cairo in late winter, take St. Louis, and - apparently - suffer nothing from the weather or attrition.
Errors on my part - in particular a lamentable lack of river gunboats! - have contributed heavily to this, but the apparent immunity to weather, the seeming ability to teleport supplies and ammo, and the repeated demonstrations that the rebs can fight just as well holed up in Wisconsin as when secure in Richmond have me baffled, balloxed, and bamboozed.
Compare this to my own advances. If I march a division into enemy territory in winter, it will die. If I send one more than a couple regions into enemy territory in good weather, the supply units may (or may not) take a beating and often the combat units as well. If I even dig a unit one region south of Nashville and don't even move it, in winter it's going to suffer, despite it being on a rail line with a totally secure supply chain. I've taken attrition losses just advancing to Fredericksburg from Alexandria in summer! I have to plan my advances region-by-region, advancing only when cohesion and supply levels are healthy, packing in the supply trains, keeping loads of rail and river transport, on hand stationing guards along the rail lines south, and building depots whenever the game lets me (which is another question - often it won't when I've satisfied all the tooltip conditions, or at least think I have).
I'm playing Halleck to the CSA's Forrest here. I'm winning, but MAN I wish I understood how the rebs do what they do. Help me to understand I beg!