What should a magus do if they either plan on declaring wizards war or believe themselves likely to be a target.
A couple things come to mind.
Besides get an AC to the other magus, get an artists rendering of the magus to boost sympathy (alternatively, take up a craft skill so you can make them yourself).
Master intangible tunnel to increase magic resistance to the spell.
Create a powerful lesser enchanted device with a one year expiry (*10 to lab total over base).
Get casting tablets for Moon duration spells. (But which ones?)
Purchase Superior Arms and Armor, potentially as items of quality.
Figure out which grog serves food to your target.
Make sure somebody can cast purification of the festering wound on you.
Set up a hidden lair with an Aegis.
Stock up on Vis (at least two rooks worth).
Get a casting tablet of Incantation of the Body Made Whole.
Invent a moon duration ward against your targets favorite mode of attack.
Get a bloodhound (many magi will not make their scent invisible).
Get spell mastery Summae/Tracti.
In-game, Wizard's war seems to be an almost completely half-hazard affair - the Wizard's War section of Hermetic Projects comments that most of the spells in there are almost completely unknown. So unless you're up against a professional assassin, he's going to be fumbling around in the dark as much as you are.
Metagame:
Determine how your Storyteller does PeVi anti-magic, and that you're on the same page regarding how it works.
Determine how your Storyteller is handling the fact that penetration is ridiculously easy to get on low-level enchanted items, and thus makes Aegis and Parma kind of pointless in an actual Wizard's War. (Not being sarcastic - the Storyteller may simply be hand-waving it away.)
(Assuming its your character that's being targeted) - Determine with your Storyteller what the narrative goals are: all the preparation in the world won't help you if the story has the Wizard's War being just a backdrop for someone's torrid love affair.
Spells.
Learn a low-level (5 or 10) Shieldbreaker and/or a generalist touch-based anti-magic effect.
Get some sort of InVi effect that allows you to SEE incoming Intangible Tunnels. (most are lvl 30 or so.)
Counter: learn some PeVi effects (Hide the Odor of Magic) that can hide from a lvl 30 InVi effect, to hide your OWN tunnel.
Generally speaking, just go out and study Vim.
Flip your specialty on your Parma over to Vim. (Is that a houserule? We play that you can do that whenever you spend XP on a skill.)
Social
Check to see if anyone is offering their services as a professional duelist, and hire them.
Don't discount your opponent social hacking you - ie, walking up and stabbing you in the back, or hiring a poisoner, or any number of different ways of killing a prepared magi.
If your opponent is smart, he would have collected arcane connections on you in the months leading UP to the issue that caused the Wizard's War.
I think that the answer to "what should you do" depends critically on which of the following two basic strategies you want to pursue:
Kill the other guy before he kills you.
Keep your skin safe until the War is over.
Almost all situations I've seen in my sagas have a character going clearly for one of the two options, though sometimes there's a switch from 1 to 2 if an attack that should have been resolutive failed.
For option 2, the typical strategies I've seen are either a) castle up (often in the sanctum of another friendly magus) or b) make yourself unavailable, fleeing to Arcadia, to some inaccessible regio etc. Castling up is typically harder to pull off, because someone who's sufficiently motivated can just pump vis into penetrating your defenses -- and unless there's a huge disparity of power, it will suffice. In both cases, making sure you have no Arcane connections lying around is very important (see below).
For option 1, it really depends on the opponent. The catch is that it has to be "surgical", because damaging bystanders is off-limits, and a smart opponent will generally make sure he stands behind many walls of bystanders. So no volcano spells. And note that "damaging" could be something as small as "violating the proscription against scrying by sneaking invisibly into the other party's covenant". Arcane connections are extremely useful in this regard, because they provide both range and precision in striking, but are also fairly hard to acquire.
So, a Wizard's War typically boils down to acquiring and retaining an arcane connection to the opponent, and/or avoiding the same fate. In most sagas I've seen, magi are very careful about destroying any Arcane connections they may leave around, and possibly disseminating a few fake ones that instead point to nasty critters with high Might. The problem with destroying Arcane connections is that they are hard to Target - most of the times you don't even know that they are around, not to mention what shape they take. Preventing their formation with some care and some judicious use of Perdo spells is typically much easier than going after them later; using T:Room or T:Structure spells allows you to Target them even if you can't sense them directly.
cash. Amass lots of cash, and mundane contacts. An assassin with a vial of poison can walk right through his ageis like it wasn't even there.
and while you are at it, don't forget the value of theft and fear. If you can make them afraid of dying to the point they flee their sanctum, ransack it for books, items, and vis.
Some will some won't, I suppose it is a troupe interpretation. But if you can manage it, travel into the Magic Realm might make for a good refuge. All AC's are temporarily interrupted, and crossing Boundaries/Vestiges causes them to decay one step. This does not affect permanent fixed connections, but those of that category, I believe, are items you will probably (and should) have AC's to and can thus destroy them that way.
Question: assume you do the Passover Solution. The other magus comes and places a watching ward in your lab. Or half a dozen of them. They go off 2 seasons later and smack you heavily, maybe destroyying any project you are working on and attacking you via PeCo spells.
Could you (if ylu survived) or your sodales pursue him for this? He cast the magic during the course of the WW after all. A WW that you were trying to avoid using legalese according to some interpretations of it...
certainly you can bring it to a tribunal. Remove the twilight and consider it- you go into hiding In the mountains for the duration of the war, and you enemy, knowing you have done this, places a watching ward on your sanctum expecting it will get you when the wizard war is over and you return, believing you are safe because the war is over. I think this would be frowned upon at the tribunal, how much depending on just how cynical the mage leaving the booby trap seems to be about it.
That being said booby-trapping your own sanctum before going into twilight...
If you gave away your lab, your adversary isn't permitted to place the ward!
But if you neglected it, then I suspect a Tribunal would a) allow the casting and b) prosecute. After all, it is fine to scry on a wizard during WW, but I don't think magi would look keenly on casting a ritual that let you scry on him for the next year. Of course, rulings depend at least as much on how many friends you have as upon what is right.
I would say yes. The whole idea of Wizard's War is that it's limited in scope (only the target), and duration (only for a month). Anything that falls outside that counts as a violation of the Code.
Or to put it another way: you can CAST a watching ward without a problem during Wizard War (hoping that your target will return to his lab during that time). But if it ACTIVATES outside of Wizard's War, you can be held liable.
I'm not sure whether this is from HP (I don't have the book), but if it isn't ... I would not allow species to act as an Arcane connection to whatever is shedding them, for two reasons.
The first is that the examples in the corebook suggest that even the least category requires something more "substantial", like shed skin from a person (and no, I would not consider "sounds made by a person" as an Arcane connection lasting days to that person). The second is that otherwise, every time you perceived a target, you'd effectively have an Arcane connection to him, so Penetration would always be counted at least twice etc. etc.
I take the opposing view. Any hostile action you take against your enemy while the Wizard War is ongoing is lawful (as long as it does not violate some other aspect of the Code such as dealing with demons, of course). If it has consequences after the War is over, it's not your business.
So casting a D:Year scrying ritual during the war would be ok, but if it e.g. created a scrying vessel, any active step you took to use that vessel (even just concentrating on it) would break the Code after the end of the War. If you crippled your enemy during the War (but failed to kill him), and that made it impossible for him to do labwork the following season, he should not be able to claim "deprivation of magical power".
MoH suggests the Pneum Flask, which captures not the words (I agree species aren't ACs) but the air your target exhales.
IIRC HP has a similar effect.
Yeah... pretty sure that would get you marched.
You may do anything during your month of War.
Once that month is over, I'd be at that tribunal, argueing that your D: Year scrying was scrying now and that this put you in violation of the Code.
Luckily, we don't have to agree and indeed it may not be desirable that w agree, because a tribunal story can be written about it if we don't, wereas if we do, because it's obvious, there's likely no story in it.
I seem to recall it went the other way: as long as you speak to a fairy, you have an Arcane connection tothefairy.
In any case, these are rules that are strongly specific to faeries.