I ran into a couple of AI problems today while playing that I thought I'd share with the lot of you. I was defending a fortress against an overwhelming force; my four retainers versus a rebellion. My main army was still a turn away so I thought I'd see if I could hold out because why not? Turns out, I could, but not by any skill. I present exhibit A: 
 

I've also had problems with the AI on assaulting the walls, though I've never had them give up.  I guess, at the same time, I've never abandoned the wall defenses.  However, the AI of reinforcement armies is simply nonexistent  - they'll only move if you send a unit to provoke them, and once that unit is taken care of, they'll return to a huddled, immobile mass.  That's probably the biggest issue I've run into in terms of battle AI, though I've never seen it be particularly brilliant, either.   
 
On the campaign AI, I have managed to take advantage of the AI's single-mindedness.  For example, as I was nearing victory in my Date campaign, I had three armies approaching Kyoto.  The first army to arrive defeated the Shogun's army, but lost enough troops that it had to retreat in the face of an army from one of the shogun's allies.  The AI persisted in chasing the one army while the other two slipped in behind and laid siege to Kyoto.   In another case, the AI had driven me from one province and was chasing the army into the next.  Rather than garrisoning the castle, I bypassed it in order to leave room for a retreat.  Even though this left my castle undefended, the AI bypassed it as well to chase my army, in so doing, allowing it to reinforce in a friendly province and ultimately win in the open field.  
 
Had some other weirdness occur too.  During realm divide, a distant faction from Kyushu kept sending naval armies to try and invade my unprotected interior.  After the first fiasco, I had two fleets in place to stop some invasions, but I let one slip by.  I sent a fleet to desperately (and hopelessly) pursue, but on the fateful turn where I expected the army to land, the fleet turned around in the water instead and ended up facing my vastly superior force.   
 
These experiences are all on normal, and so may not be representative of the AI's full capabilities.

Creative Assembly hasn't improved their AI since Medieval II. It's one of the reasons I'm completely boycotting their games until they fix it; the last game I bought was Empire which was a total disappointment (fences were apparently impassable barriers to American revolutionaries).

" Creative Assembly hasn't improved their AI since Medieval II. It's one of the reasons I'm completely boycotting their games until they fix it; the last game I bought was Empire which was a total disappointment (fences were apparently impassable barriers to American revolutionaries). "

Ever heard of mods, brah?

Sometimes devs build AI under preconceptions that "of course the player is going to ____" and you get shit like this. Its like with older RTSs. "Of course they're going to fully barricade, so we'll have the AI look for an opening". Then you proceed to build a mouse maze for them to walk through and build towers or archers nearby (depending on the game) and watch their whole army die in the maze.

"@Geno said:

" Creative Assembly hasn't improved their AI since Medieval II. It's one of the reasons I'm completely boycotting their games until they fix it; the last game I bought was Empire which was a total disappointment (fences were apparently impassable barriers to American revolutionaries). "

Ever heard of mods, brah?

"

I think the AI is getting better. They make better use of mountains and cover terrain. I even lost a couple of battles (well, mostly siege) against AI on normal. That being said winning against double the force on plain terrain is not uncommon. On the campaign map it makes more use of distances (attacking a province before you can rush back to defend). I haven't played on higher difficulties yet. Empire on the other hand was easy even on very hard on both sliders (now a single slider in Shogun 2). 
 
Last defense I won with only 1 additional unit was luring a couple of yari units around the battlefield with my single light cavalry unit until they were exhausted and barley could climb the wall.

" Sometimes devs build AI under preconceptions that "of course the player is going to ____" and you get shit like this. Its like with older RTSs. "Of course they're going to fully barricade, so we'll have the AI look for an opening". Then you proceed to build a mouse maze for them to walk through and build towers or archers nearby (depending on the game) and watch their whole army die in the maze. "

" I think the AI is getting better. They make better use of mountains and cover terrain. I even lost a couple of battles (well, mostly siege) against AI on normal. That being said winning against double the force on plain terrain is not uncommon. On the campaign map it makes more use of distances (attacking a province before you can rush back to defend). I haven't played on higher difficulties yet. Empire on the other hand was easy even on very hard on both sliders (now a single slider in Shogun 2).   

I've only played the demo, so maybe not representative of the final game but when I was assaulting a castle I set my archer up outside the wall and just had them rain arrows down on them and they simply stood there and where cut down by arrows. Eventually I figured out that I could climb walls, ran around the castle climbed up got above the remaining guards and just shot arrows at them till they died. They did nothing to retaliate.
 
Kind of a bummer.

Seriously... if creative assemblies would wait a few extra months in between total war releases and worked entirely on the AI, I dont think ANYONE would care.... if they ever do fix their AI it will probably be the greatest game i have ever played =p

Every time I'm in a siege battle involving reinforcing armies, the AI's reinforcing army always just lines up and waits there, not moving. I had a battle as the Hojo, a full stack in the castle vs 3 stacks of Takeda, and after dealing with the first stack the next stack just camped themselves in a valley until the hour was over.

Yeah, I had a similar issue, I wouldn't call it a problem though. I had two Yari peasants and my retainers and by first holding the corner (they always seem to climb the wall at the closest corner) I managed to rout almost a full stack of Samurai and Yari men. I had to flee from their arrows alot, but so long as you stay close to the walls then the cover is good. Then the archers and the general attacked. To make the archer climb the walls, just hide at the opposite end of the fortress and then charge them when they get to the wall. Then they have to face two units basically one by one. The general killed a few of my dudes and then fled. However, this was on the smallest castle. I tired a similar thing with a few more guys against a few less of theirs on a big castle and got surrounded and picked apart.