Implications of Gurps Magic on a Merchant Princes-like setting - advice needed

[Anaraxes]

If magic is so recently rediscovered that it's not widely known, or believed in, then there's an edge there for the mages (particularly the PC mage) in that people in the setting won't be prepared to deal with magic*, there won't be common access to anti-magic dispels and wards and so on, and it won't readily come to mind as a explanation. That is, it's all the same things the GURPS Powers lumps into "countermeasures". It's also the classic case for the Unusual Background Advantage, in this case a surcharge just to represent the increased effectiveness of Magery and GURPS Magic in a setting where magic is much more scarce and unknown than the presumed default for Magic.

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* scrying on enemy plans, mind probes and mind control, Apporting objects through portcullises, Body of Air slipping through cracks, remote viewing and teleporting into the vault... many, many tricks that a merchant prince would find invaluable that aren't overt combat spells or direct economy breakers. If the NPCs can't reasonably be guarded against that because they don't know about magic and aren't prepared to counter it, then the PCs will just run roughshod over them.

[dcarson]

For a merchant prince finding out a day earlier then everyone else how this years grain harvest went in country we ship grain from to here is a major thing. Lets you buy options or short the market knowing it will work. See the movie Trading Places for a worked example :-).

[Anaraxes]

Originally Posted by dcarson

For a merchant prince finding out a day earlier then everyone else...

Or even hours. One of the early popular applications of the telescope (in the real world) was by merchants, to spot incoming ships before they arrived at port. Knowing a ship was inbound gave them enough time to get a jump on the competition. If it were a friendly ship, or you knew its flag code, you could even get information on the success of its voyage and any opportunities from unexpected changes in the manifest.

[Black Leviathan]

I wouldn't rely on a spell difficulty or college to determine the danger of specific magics. Very simple magical effects could blow your economy off kilter. I'd go through the whole list, look at the description and think about how it could be used in your setting. Categorize them as "Safe", "Risky" or "Game-breaking". Just toss out any game-breaking magic outright as Lost Magics. Let the players have access to any of the safe spells at the start of game. If prerequisites are lost magics, tough luck, there are lots of other spells that are available. Consider letting the players get their hands on Risky magics as the game progresses and they can do less harm to the setting.

[WhiteFox1618]

People have mentioned restricting VH spells... I might suggest limiting the level of Magery that PC's may start with, or restrict spells that require a certain level of magery, because there just haven't been enough wizards of those magery levels to discover them yet... "no spells above Magery 0" puts most of the Gate college out of bounds, and the Enchanting College doesn't even start until Magery 2.

Also worth considering is the total number of CPs that can be spent on magic traits... [1] point in a skill equates to about a month of study. So if, frex, magic has only emerged in the past 1.5 years, the PC's could only have been studying it for that long, and they'll be limited to 18 points in spells at most (adjusted by +10% per levels talent, and/or teaching/intensive training, if those are even available. For there to be teachers available, someone has to have figured out the spells in the first place).
Similarly, you might include points for magery in that tally. I was in a campaign where PC's were limited to maximum of [30] in magical traits to start, and deciding between Magery 2 and [5] in spells, versus magery 1 and [15] in spells was... a painful decision. (Fortunately, events in the campaign transpired such that we got to improve our magery levels, and we were using wildcard magic, so picking up new spells wasn't really an issue, though it took a while to pick up new colleges).
If you want to avoid the "wizards spamming fireballs every other round" kind of spellcasting, mandating a combination of Ceremonial Only and Solitary Ceremonial modifiers turn magery into more of a drawn out, meditative, process. That's mainly a question of campaign tone, though.
Another option is to introduce material requirements for all spells. Maybe every spell requires 50$ of a particular material to cast (a pinch of diamond dust, or a gold half penny, or somesuch).

I don't think this has been mentioned yet (I know divination spells have), if the setting has Alchemy in play, or if it's available to the PCs alone, mind the Food college. Several spells interact with potions (Mature, Know Recipe, etc).

Even without Alchemy in play, the Distill spell could brew some mundane, though blindingly powerful beverages (literally), and significantly accelerate alcohol production. That has potential for economic abuse... using Essential Food on wine such that it's guaranteed not to spoil as it ferments would also add a degree of economic exploitability (Unless the GM rules that fermentation constitutes a type of "decomposition," which it basically is, in which case Essential Food could prevent fermentation, and be used to sabotage a vineyards production).

[maximara]

Originally Posted by Black Leviathan

I wouldn't rely on a spell difficulty or college to determine the danger of specific magics. Very simple magical effects could blow your economy off kilter. I'd go through the whole list, look at the description and think about how it could be used in your setting. Categorize them as "Safe", "Risky" or "Game-breaking". Just toss out any game-breaking magic outright as Lost Magics. Let the players have access to any of the safe spells at the start of game. If prerequisites are lost magics, tough luck, there are lots of other spells that are available. Consider letting the players get their hands on Risky magics as the game progresses and they can do less harm to the setting.

This is the best way to handle things IMHO. People tend to gravitate to the flashy spells and fail to realize that other spells are just as powerful but in different ways.

Take Copy for instance. Enough people know it and you have the equivalent of the Printing Revolution without actual printing presses.

Preserve Food, Create Food, and Essential Food would similarly be powerful spells in TL4. Armies of that time generally had to trade with or raid the local area for food as it just wasn't practical to have a mammoth supply train with the army. Heck, this was a problem clear into TL5.

Personally I would go for a more "standard" magic was a forgotten science method with what remaining being the Ritual Magic system with a very limited spell list.