I disagree. I think many of the specific items listed being in multiple books is a serious impediment to new players when they are told “well to really understand how to build that concept you need to read these other books.” This seems particularly true for a very common concept like a Summoner of any stripe except a necromancer but also for things like craft magic so having those things in one place would be nice.
I agree that the basics of Initiations should be in core, there are 4 houses that use the rules for their apprenticeship. That said, I think it should be a trimmed set of the rules with one sample script for each outer house mystery and not include in-character change or creation of initiation scripts. Sure, tell the SG how to build them but rules for characters to do that within the game seems extraneous to the Core book to me.
I am of the same frame of mind as dc444. Most of my suggestions are ether for things that should have been in the Core book because of need by a House (Mundane Beast, Supernatural Ability rules), there are corrected versions & having more of them would be valuable (Spell Guidelines, Virtues & Flaws), or they are scattershot across 4+ books which sometimes conflict with each other (Shape & Material, Craft Magic, Spell Mastery).
I would gladly chunk my suggestion of "Lab & Lab Activity" if we could get clear consolidated sections on the important stuff. Though I still think including "Casting Tablets" would be pretty easy since it is only a paragraph.
Most of what I would have said has been mentioned by other people already so I won't retread that. I will highlight mystery initiations and original research as the two that I would view as absolutely essential because they are key to the core experience of a lot of magi characters.
One that I don't think anyone has mentioned are the agent rules tucked away at the end of HoH:Societates. @Heaven_s_Thunder_Ham mentioned people being confused as to how characters are supposed to (mechanically) acquire new grogs or companions, especially magi with the gift and all.
IMO the Magus/Companion/Grog hierarchy is so intrinsic to the game that mechanics for getting and managing subordinates in play ought to be a part of the core rules. Or a cut-down version of them, maybe.
Mystery mechanics, including those for the unGifted.
Childhood mechanics: Characteristic modifiers, gaining/losing Virtues through aging and training.
Labor point mechanics. These are crucial not only for craftsmen, but for companions and grogs unsupported by the Covenant such as knights (see Lords of Men, p.69, Tournaments as Income).
The Book of Beasts, extremely useful for designing animals.
Original research and Hermetic integration mechanics. Including "lightweight" integration of e.g. a single ritual (like The Gaze of Ra, from previous editions).
Craft magic mechanics - including the role of Finesse rolls, the appropriate characteristics (Int or Per), and modifiers for complexity/flexibility.
Not quite rules, but a slight clarification on Houses that makes sure the first impression in the core book matches that in the three HoH books. For example, one should be made aware that shapeshifting other than through the HeartBeast is a big taboo for Bjornaer magi.
A clarification on whether rituals count as formulaic spells or not, and if not under which conditions they cannot botch.
A clarification about species, light, shadow and invisibility.
A clarification about spell targets that involve sets of individuals - e.g. Group or Room: how they work when an individual joins or leaves the set (e.g. the Room, or the Group) after casting.
A clarification about what counts as "inside a Ring".
A clarification about size modifiers for spells that change the target's size.
A clarification that Certamen botches do not award warping points, or a season of Certamen practice would send anyone into Final Twilight.
A clarification about the rough "scale" of supernatural Might: from later supplements, one gets a strong sense that 100 is the maximum (Lucifer, the Virgin Mary, the greatest Protogonoi) but it's never stated explicitly and it was not like this in previous editions.
A clarification that spell guidelines (and Shape and Material bonuses?) in the corebook are examples, and should not be considered the totality of what can be achieved .. but that not everything that fits within the limits of magic is within current Hermetic understanding either (e.g. making species solid).
A clarification about who can help in the lab, and how (there are still debates about whether/how an unGifted Failed Apprentice can add his Int+MT).
The clarification in HoH:S about exerting magical force (possibly with that in TME about how much force Rego magic can apply), and magic resistance.
Casting tablets. If they exist, it's a big difference, in that no PC needs to spend a season or more to learn that "cast once" ritual.
Last but not least: early on, a clear, general unless overruled, clarification about ROUNDING.
B. POSSIBLY (i.e. I'd like to find them in the core book, but I would not be too upset if they were not).
Ceremonial spontaneous magic from HoH:S.
Debate mechanics (I really like those adapted from Dynasties and Demagogues better than the ones in HoH:S).
The revised mechanics for faith points in RoP:D, and possibly those for pilgrimages in TC (alternatively, the latter can be given as Mystery mechanics)
Examples of warping for other mystical traditions.
Not quite mechanics, but the idea that Demons lack Virtue, so they can be foiled because they are the essence of Pride, Sloth, Envy etc.
The existence of the Magic Realm - just a paragraph mentioning it! - and the "unchanging" nature of magic.
The rough guideline from HoH:S for creating new Supernatural abilities.
Agency and loyalty mechanics (from HoH:S, C&G, and ... elsewhere too, I suspect).
Slightly extended spell guidelines, spell masteries, and Shape & Material Bonuses.
The clarification about the different types of mystical shapechanging (from the Bjornaer chapter in HoH:MC).
The clarification about the final key to Parma magica being taught only at the end of apprenticeship.
Intrigue and area lore mechanics.
A guideline for how many Twilight scars (and whether positive or negative) a magus who's build on the "2 Warping points/year" guideline is supposed to have.
A hermetic technology table, giving an idea of how hemetic magic has progressed through the centuries (e.g. Conciatta's four Realms Theory) and how it may progress in the future. This is extremely useful if one wants to play a very long-running saga or one set e.g. at the time of the Schism War.
Right, but my point was "more is not always better" and in my previous post I was suggesting to add rules to summon and bind elementals, for necromancer from True Lineage (Tremere) and rules to build a Ex Miscellanea from Societas because like you I think it is popular archetypes and the rules are really usefull.
And it's not that I don't like the others suggested rules, I just think that very specifics rules are better in supplement than in the core rulebook (and it's convenient to not have a too heavy rule book to carry)
The Lab customisation rules from Covenants. All sagas have magi, all magi have laboratories, Lab customisation options drive a lot of interesting story. Either by making laboratories more vivid, or by the in-game acquisition of bits and pieces for lab customisation.
The book of mundane beasts. Always handy to have some creature stats. Plus, (perhaps) a greater selection of critters from the realms (where that can be done without introducing a lot of rules).
Templates for older magi.
Consolidated shape + material bonuses.
Mystery initiation (and some example scripts).
Not so much rules but text content; it seems like there are some inconsistences between the Realms as described in the core rulebook, and what is described in the appropriate realm books. Some relatively minor changes could perhaps smooth this out.
Finally, I would argue against integration and original research rules being in the core rulebook. I believe that these are only relevant to a small minority of sagas.
Some things that would be very useful to have in the core rulebook instead of in various other books:
Rules for how to calculate penetration for Supernatural abilities.
The various spell guidelines, spell mastery abilities, and Shape&Material bonuses, that are usable to all Hermetic Magi.
Some of the various Virtues and Flaws that have been added, namely those that are not specific to any particular group and that does not depend on the rules in any of the supplements.
Stat blocks for various mundane animals.
Basic rules for magical animals.
This information is needed for: Bjornaer Heartbeasts; Animal Companions and Magical Animal Companions (as per the Story Flaws); Familiars.
Some of the rules from the Houses of Hermes books that are universally applicable. For example the rules on invisibility in combat from the Flambeau chapter does not have anything specific to do with House Flambeau other than many of them being combat mages.
A brief description of each of the Tribunals, similar to how we get a brief description of each House.
Rules for things like mysteries, or lab customization, or rules on how to make theriacs and formulae, and many other specialized topics do not need to be in the core rulebook, and are in fact better placed in separate books where those topics can be dicussed in detail.
I must argue strongly against original research being in the base book. These are very advanced rules that require a level of mastery of the system, not rules for a first game or for a player having just one rulebook.
Looking at this thread and seeing long shopping lists makes me wonder whether we understood the question asked the same way.
Sure. Different opinions are perfectly normal. The thing is, the thread is called rules that should be core. But the first topic talks about rules that should have been in the core rulebook. These are two entirely different subject, and I feel as though not all of us are answering the same question. Because if we're looking at core content rather than rules that were needed in the core rulebook then my answer becomes very different!
Hey, there already are on the corebook!, on page 184. They deserve to be placed in a less obscure place (like in the Abilities chapter), definitively. Having to look on the Realms chapter under a section named “Magic resistance and penetration” isn’t exactly intuitive.
I’m loving all of the suggestions, but I’d say moving many of them into the corebook would make the book where they are quite redundant: the rules for Original Research are quite cool, but they are supposed to be a theoretic and bonisagus-ish stuff. Also if I were reading the book for the first time and while struggling to get the complex magical system I were also reading “but hey, there is even more!”, I’d probably be overwhelmed.
So I’d look either for not so important books (hello, combat option from Lords of Men), stuff that transcends the book it’s on or thins spread into many other books. So from Covenants, Craft Magic and Casting Tablets smells core enough, but lab customization options doesn’t. And Mistery Initiations would fit into the corebook because they are used for Mistery Houses, Cults and hedgies.
Many people have said that mystery initiations should be in the core rulebook.
I disagree.
While mysteries and mystery initiations are really cool, they are not needed in the core rules - other than a brief mention that they exist and are described elsewhere.
Mystery initiations are not needed unless you have mysteries to go with them. The only mysteries needed in the core rules are the outer mysteries for the for Mystery Houses, and characters from those houses start with the outer mystery already initiated.
For more details on how mysteries work you need a whole lot of pages to give them the treatment they deserve - pages that will crowd out other material. Meanwhile, mysteries are not really needed for an Ars Magica saga, nor are they needed for most character concepts. They are one of those things that, while cool, one can so easily do without.
And, importantly, mysteries can easily be added to any saga without having to retcon anything in that saga. The average mystery cult is secret after all, so not so strange that no characters had heard of them before.
One thing I haven't seen mentioned, is the choice of House Virtue for some of the Houses. Some of them list one option only, but the HoH books added a few to some of them, and that should be in the core.
At the very least Mystery Cult Lore should be added to the ability chapter so beginning characters within the MC houses take it rather than having to make an exception for members of those houses apprenticed within them as they did so characters built before The Mysteries or HoH:MC did not need to be altered. And I would argue that the additional uses of faerie magic and Enigmatic Wisdom should be in Core where those mystery mechanics are defined in the Hermetic Magic section.
For consistency, and to get rid of one piece in the errata, it would be nice for the Faerie Magic Virtue to grant the Ability at 1 like all the rest do. Sure, in the core book it may be a fairly pointless thing just like Heartbeast Ability, but it would be helpful to include this.
They already do. And the Merinita in the core book was originally given the Faerie Magic Ability. As it hadn't been set as an Ability yet, it was removed in the errata. And then Faerie Magic showed up as an Ability in HoH:MC.
However, that does need to be noted among the hard-to-find rules.
One thing that's not in the corebook though is how to calculate penetration for supernatural ... stuff without an Ability associated with it. For example, if you are a transformed skinchanger (a constant mystical effect as per HoH:MC), what's the effective penetration of the effect? How about a straying
Nightwalker (from HMRE)?