I thought we might gather some of the hints for playing through the games that didn´t make it into the cluebooks - Ultima IV and V are certainly tricky enough to figure out on their own. Ultima VI, on the other hand, has a walkthrough in the back that looks pretty complete, but if that one missed anything, feel free to add it.


Let me begin:
The mantras for the eight virtues are the same in each of the three games, and the Ultima V cluebook tells you who to ask for them there.

In Ultima V, if you drop a coin (Look command) into the well in the courtyard in Empath Abbey, and wish for a horse, you will get one.

Make sure to read the tombstone inscription (Look command) in the various graveyards; some of them contain good jokes - like "Here lies poor Richard, buried alive, trying to solve Ultima V"

In Ultima V, the password for the Resistance is "Dawn", the password for the Oppression is "Impera" (the imperative form of the Latin word for "to rule", which I guess is fitting)

The Shadowlord of Hatred is called Astaroth, the Shadowlord of Cowardice is called Nosfentor, and the Shadowlord of Falsehood is called Faulinei. (Nothing is more embarassing than to summon the wrong one at the critical moment...)

The word of power for the final dungeon in Ultima V, Doom, is "Veramocor". You need to have destroyed all three Shadowlords and collected the Sandalwood Box, the Amulet and the Sceptre; I am not entirely sure if you need the Crown, but it helps tremendously (I consider demons, in particular, to be invincible without the Crown), and I am almost sure you cannot reach the location of Doom without the Magic Carpet. You need the Black Badge, which you can get in Windemere, in order to have any chance at retrieving the Crown from Castle Blackthorne.

For my part, I would be grateful to learn where, in Ultima IV, I can find the runes of Spirituality and Valor, and how to get past the demon hordes that guard the Shrine of Humility.

You don't actually NEED the black badge to get the crown, all you really need is the magic carpet for outrunning guards and some skull keys if you wanna open some magically locked doors.

For the Rune of Valor, you need to find a way inside Jhelom's well-guarded walls. There's a secret wall in the Inn (look for a small white dot in the brick texture) that lets you into the town's walls. You'll need to go in here with Dispel magic, as there are magic fields blocking your way. The Rune is located in the southeast "tower."

The Rune of Spirituality is actually in Lord British's castle, behind a secret wall on the first floor (in what appears to be the guards' barracks) where there's a lot of treasure chests. It's not actually in any of the chests, you need to (S)earch the ground while standing on them. Do not actually (G)et any of the chests or your Virtue will take a hit!

As for getting to the Shrine of Humility, you'll need the Silver Horn. Blow it every few steps as you're walking to the Shrine and you'll prevent the endless hordes from attacking you. (You should also blow the Horn on your way back.)

Thanks, that helped a lot.

Now I have two more questions.
First, how do I get the SIlver Horn?
Second, what are the altar rooms at the bottom of each dungeon good for? I can´t seem to interact with any of them.

I figured something else out, by the way - not really crucial to solve the game, but good to know nonetheless. In Ultima IV, when you invited characters to join you, you´d often get "You are too inexperienced for me to join you" as a reply. Apparently, the maximum number of party members (including the player character) is equal to the player character´s level.

Have you been to Magincia? Talk to a skeleton named Banter there. You should find him near the top left corner of town. He should lead you, indirectly, to the Silver Horn. Talk to Zajac in the Lycaeum. He should lead you indirectly to an important clue as to the use of the altars.

They also handily connect all the dungeons (except The Great Stygian Abyss, to which they have a different link) together, just in case you want to explore more than one. AND - you're going to need a complete party, consisting of one representative from every class (Fighter, Tinker, Bard, Druid, Mage, Paladin, Ranger, Shepherd). And the experience requirement for each level is double that of the previous.
You will need 6,400 experience, at the minimum, to complete the game (although it caps at 9,999). I would refrain from collecting your last three or four characters until you hit level 8, so as to avoid dividing the experience too much and making that last 3,000+ a real struggle. The game seems to scale its difficulty (seems to, anyway) to match the number of people in the party when it comes to random encounters, so unless you want to actively hide some of your characters... My method has been to grab the three or four I intend to make my "main force" and use them until the prospective avatar is level eight (and my backup band is six or seven) and then fill out the ranks. The newbies will level faster and reach a reasonable (survivable) level fairly quickly, while the old hands will stay stable. This beats struggling to keep every one of your patry members alive at level four or five!

You get at least 5600 XP from collecting all the items. Reaching 6400 XP isn't a struggle at all.

What the games don't tell you about experience:
The requirement for level doubles every time, and in keeping with the arc number of the series, there are eight experience levels, requiring 0, 1, 2, 4, 8, 16, 32, and 64 (x100) experience to achieve.
In Ultima IV, you have to speak with Lord British to level up (as in Ultima III, by the way) but you don't need to ask him anything - he just does it automatically when you start the conversation.
In Ultima V, "a mysterious yet familiar figure" sometimes shows up in your campfire when you camp; he'll heal the party and conveniently level up anyone who has made it to the threshold
In Ultima VI, you need to Talk to one of the shrines. Yes, you read that correctly.

In Ultima IV, the only result of levelling up is more HP. To boost your primary statistics (Strength, Intelligence, Dexterity), you need to touch magic balls in the dungeons. This is painful (minimum of 200 damage per use), but effective. Carry lots of ginseng and spider's silk.
In Ultima V, the firey figure will boost one primary stat at random by one point when you level up.
In Ultima VI, your stats go up with your level, but which stats and by how much depends entirely on which altar you speak with.

In Ultima IV, you recieve 100 hps per level. In Ultimas V and VI, you recieve 30 per level.

For an extreme spoiler, the horn can be found here

http://moongates.com/u4/tilescripts/Worldmap.asp?lat1=10&lat2=13&lon1=2&lon2=13&items=Y&printable=Y

It's also an interactive map the will show you the location of just about everything.

In Ultima V, you also get stat boosts from finishing shrine quests, according to which principles the virtue of the shrine is linked to (+1 Strength for anything linked to Courage, for example), but it seems not every companion receives every boost. My current theory is that only the Avatar and fighter companions get Strength boosts, only the Avatar and bard companions get Dexterity boosts, and only the Avatar and mage companions get Intelligence boosts.

I thought you also got XP (100 each or so) for doing shrine quests, but I didn´t seem to get any so far.

I'm pretty sure only the Avatar gets stat boosts from the shrine quests.

Here´s another one:

It´s not actually necessary to fight all the way up through Hythloth in Ultima IV - just enter through the rear entrance, then cast X-it in order to be deposited at the front door. Since Hythloth doesn´t seem to have a stone to recover (according to the cluebook) you shouldn´t miss out on anything important.

Hythloth doesn't have a stone. And you can get to it from any of the altar rooms, too.

Oh, hey, while we're on Ultima V, there's a guy hanging around Lord British's room, looking for a party to join. Consider him very carefully before taking him. Familiarize yourself with his name, so much that you know it back to front.

Meh... if Lord British can be blind enough to entrust his realm to someone called "Lord Blackthorn", why should I be more careful? ^_^

Because if you let this guy in your party, he'll make off with a VERY plot-critical item that will be very difficult, or at least time-consuming, to get back. To the point where most walkthroughs I've read suggest, or at least imply, that you'd almost be wiser to simply start a new game if that happens.