Let's look at a certamen round.
0. If this is the first round of certamen, Initiative is rolled.
Both magi choose independently which Art to Attack and which to Defend with.
First half-round: the attacker is the magus who won Initiative the first round, the defender the magus who lost.
The attacker rolls Pre+Art+stress die.
The defender rolls Per+Art+stress die.
The attack is successful if Attack Advantage, i.e. attacker's roll - defender's, is positive.
The Weakening Total is computed as Attack advantage + (attacker's Int + Penetration) - (defender's Sta + Parma) and the results applied.
7-10. If the defender is still conscious, attacker and defender switch roles and repeat steps 3-6.
Exactly when (or more precisely, immediately before or after which step during a given round) must the magus who won Initiative (i.e. the attacker in the first half-round) declare use of vis to boost his attack, at the very latest? How about vis to boost his defense? And the magus who lost Initiative?
I'd be tempted to say that steps 3-6 are simultaneous and "near instantaneous", so both magi must make all vis choices for the first half-round immediately after step 2 (and all vis choices for the second half-round immediately after step 6). But I could see people arguing that e.g. the defender can delay his choice for the first half-round until immediately after step 4 or even step 5 ("feeling his phantasm faltering under the blows of his opponent's, the magus decides to draw on his meager stores of vis...").
I would say whenever you want. The Certamen dual is a quick way to resolve what is supposed to be a lengthy conflict, and if it is important enough to each participant to keep pouring in vis, then yes, that's how it could go. The use of vis should be about a calculation of cost versus benefit, not trying to outguess your opponent.
I would point out that, from a number of "tests" our troupe ran, this is a choice that can drastically alter the tactical nature of certamen, and a lot of the strategic choices around it.
For example, if the attacker must choose the amount of vis and then roll, and then the defender can choose the amount of vis and roll, that's a great advantage for the defender - and you can expect far fewer challenges. If both attacker and defender can keep pouring vis in a "bid war" even after the dice have rolled for that round (like confidence), the advantage of the stronger magus (in terms of Arts and available vis) becomes much larger, outcomes become much more predictable and you get a much more "might makes right" Order. If each party must choose without any knowledge of how much vis the other will spend or of the outcome of the rolls, Guile and Folk ken become more important, while at the same time certamen becomes a much more unpredictable arena where many resources are likely to be wasted and stronger magi are less dominant.
The relative strength of some styles is also radically altered. In Andabatus vs. Hoplomachus, for example, Andabatus is weaker in a "bid-war" certamen, even more so in a "defender-can-respond" certamen, but equal or even slightly stronger in a "blind-choice" certamen.
At the same time, defining when vis can be spent can yield different interpretations of what actually happens during certamen. Is it a fast-paced, gunslinger type of duel where you have no time for assessing what the other person is doing before an exchange of blows is over (blind-choice certamen)? Is it more like a chess match (bid-war certamen)? Etc. etc.
I know it doesn't say that using vis in Certamen adds botch dice, in the Certamen section. It's clear from the rules for spell casting that using vis under stress adds botch dice. And while it isn't stated explicitly in the Certamen section, it's pretty reasonable to interpret that botch dice are add for Certamen, because the limit on the number of pawns that can be used and the bonus to the die roll are identical.
It adds botch dice to the casting roll, yes. This is stated explicitly.
Ah, but that's the point.
The certamen section gives its own mechanics for vis use.
Some mechanics are identical to those for spells, but are still given explicitly.
It then stands to reason that the certamen section on vis use should be read as self-contained.
So if it does not mention vis use adding botch dice, vis use does not add botch dice to certamen rolls.
Using your argument, one would have to consider "pretty reasonable" that using vis adds botch dice to Finesse rolls, to Concentration rolls, and to the stress roll one makes when experimenting in the lab when using vis. That's not the case, in my opinion. Using vis adds botch dice only to those rolls for which it is explicitly stated to do so. For example, spellcasting rolls. Or rolls for vis study.
No, because vis isn't part of Finesse or Concentration. That is a specious comparison. Vis in the lab, is vis in the lab. Finesse and Concentration aren't Arts and have no role involved in the rolls of spell casting and happen to subsequent to it. In your games, play without adding botch dice for using vis in Certamen. It's certainly something in need of errata, as to some it seems clear that you would add botch dice and to you you take the lack of mention in the Certamen section as meaning you don't add botch dice.
I can appreciate your stance, and I already stipulated it wasn't explicit, but it isn't reasonable, it isn't consistent with vis use in spell casting, which is closer to Certamen than using vis in the lab. I also have something of an issue of a player being potentially penalized for using resources, in Ars Vis is money, like gold pieces in that other game, rare is the player taking significant risk by spending his gold. Then again spending gold happens outside the actual playing session, so if one wants to affect a significant change by spending mass quantities of vis, there probably should be some element of risk involved, being able to add huge bonuses to the die roll shouldn't be risk free.
It specifically states that spending vis adds +2 to the attack roll or defense roll, not that it adds a bonus and botch dice. It also specifically states that vis may be spent at any time, which would include after the roll was made.
Yes, I stipulated to that. In my first post, responding to ezzelino.
I find it unreasonable. Certainly inconsistent with the spellcasting rules. And while they are not identical, they are both Hermetic Arts involved, adding vis to spells isn't risk free, so to should it be for Certamen.
So something these specifically fail to mention, in a place where it would make sense to mention if they were in fact part of the rules, you just look at that and say "well obviously it is in there because they didn't say it wasn't"? They also didn't mention fish spontaneously falling from the sky- is that part of Certamen as well?
This is something that cuts both ways, it's not as if it's against the players. Indeed, it's probably beneficial for players to have a risk of botch as NPCs can have vast quantities of vis at their disposal. If they don't have anything to lose by using it, then they will probably use it, since Certamen is used to settle disputes...
Let's not go down that avenue, the rules would be long and impossible to use if everything that wasn't so needed mention.
I'm in the camp that find it reasonable to have vis use in Certamen come with a risk of extra Botch die, similar to vis use during spellcasting, even as it grants the same bonus. So I think if there was an exception to Certamen this would have warranted a mention. It could have been an oversight, and the rules as intended may have been like that. But there are some parallels between spellcasting and Certamen anyway, like Concentration rolls.
In fact, I had never even considered that there could be an exception for Certamen. We've not used much Certamen, and I don't think anyone ever used vis.
I find both extreme ends of rules interpretation horrible: "Unless it is clearly stated that you can then you can't." or: "Unless is is specifically stated that you can't then is must be legal". The rules can't be exhaustive about things you can't, and ideally there should be mention of things that aren't clear cut one way or the other. Due to interpretation of the readers it is hard to catch it all. What makes perfect sense for some may be read the other way by some, and this is hard to predict, if you can't see any logical arguments for another interpretation.
In regards to botch dice, I think there are two related but fundamentally different questions here.
The first is: does having vis add botch dice to certamen rolls make sense as a rule? This can be debated at length, and I guess depends a lot on individual sagas and player sense of "game aesthetics". Personally, I think it would make sense: it would make things more "homogeneous" with the rest of the system. However, I do note as an aside that certamen can get fabulously expensive in terms of vis use - so I'm reluctant to add an additional cost to a choice that is already exceedingly harsh (so harsh, in fact, that few troupes seem to ever have their players make it). Personally, I would have rather ruled that a magus could add fewer pawns to each roll, with each pawn having a greater impact: let's say one pawn per magnitude of the Art score, with each pawn adding +5 to the total. In this case I would have been even more favourable to having certamen vis add botch dice.
The second question is: how does one read the rules as stated? Everybody accepts that the current rules do not state explicitly that botch dice are added, either specifically for Certamen or generally (something like "using vis in magical activities always adds botch dice"). Moreover, and I think this is a very important point, a lot of other stuff that Certamen has in common with spell casting is explicitly mentioned. Obviously, one can't assume that I do not go jogging in winter because I never said so on the forum; but had I stated that I go jogging "in spring, summer and autumn", I think the most reasonable reading would be that I do not go jogging in winter - and I would find rather strange if someone said "well, ezzelino mentions jogging in spring, summer and autumn, and thus it's natural to assume ezzelino jogs in winter too".
BUT ... let's go back to the original question! When is the last time to declare vis use? If one assumes that the vis adds botch dice to a roll, the answer is obviously no later than the roll - but it could be earlier, e.g. at the beginning of the round, so as not to give an advantage to the defender (who can otherwise adjust his choices to the choices and roll of the attacker). If one assumes that vis does not add botch dice, both parties could indeed keep pouring vis well after the dice had rolled, a pawn at a time (just enough to top the adversary's last total) as in an auction - until one ran out of vis or out of "Art score".
Since using vis in Certamen is not specifically stated to be similar to the rather unique mechanics of Confidence, which can be used after the fact so one can decide whether it is worth the bother, it needs IMHO to be used before the die rolls.
Yeah, I agree with this. When I see any time, I'm thinking attack or defense, not post die roll.
I can get behind that as a house rule. With great risk comes the potential for great reward. +5 is a huge bonus, +2 is mediocre. I wouldn't even limit it so much as you do, so long as they have to face the risks of botching. If you remove the botch risks, then I would limit it to Art/5.
I don't find the rules to be exhaustive, though. And Ars needs more table agreement than most games to decide how things work. If you instead said I only jog in the spring, summer and autumn, I would know instantly that you don't jog in the winter. Similarly, if you said I don't jog in the winter, it's an implication that you jog in spring, summer and autumn, but it's not explicit. There are many places where the rules are ambiguous. Perhaps you don't generally jog in the winter, except on days where it's above 40? For example, I think the rules, despite David Chart's comments about the subject, require botch dice for rituals, which includes the pawns of vis used. The rules don't explicitly state that it is necessary, that that mastered rituals spells can be cast in a relaxed manner, it says mastered spells. Is the distinction between ritual and formulaic important or trivial? Some may not find this ambiguous, but why bother defining the difference between ritual and formulaic? Why bother saying that rituals are stressful (to me it means they need a stress die that can botch, not a non botching stress die like a relaxed mastered formulaic spell).