There are some invocations which seem to be able to help you quite a lot in intrigues (or narrative scenes with some form of "social conflict"), I am thinking mostly of things like Matsu's Battlecry, Vapor of Nightmares, Fukurokujin's Wit and Courage of Seven Thunders, which mostly influence strife/composure.
I suppose, they are actually 'not allowed' in such situations (or prior to them as "preparation") or am I wrong in thinking so? If you would use them (or attempt to do so) nevertheless and get caught (which is most likely going to happen, if you are no Soshi Illusionist), what would be the consequences? Loss of glory, I guess, but apart from that, would there be other repercussions, some sort of punishment? Would the other side in the respective social conflict automatically "win", since you tried to use unfair methods, and would you lose some honour for playing unfair? Are such uses of invocations even deemed "unfair" or are shugenja allowed to use them, however they want, as long as it is in their lord's interest?
With other invocations it seems more clear, since I guess you are always allowed to use invocations for healing and such things, while using invocations to spy is still considered spying (and thus probably dishonourable or even illegal?), but regarding the mentioned invocations I'm really not sure how their application outside of martial combat and especially in court and similar situations would be seen. I would be glad, if you have some enlightenment for me 😀

As a bonus question relating to the above: Do you actually need line of sight for such invocations?

Invoking Matsu's Battlecry or the like is on the same level as drawing your weapon and attacking someone. If you get caught, expect to be treated the same way as a bushi getting violent in that same situation.

Line of sight: good question. I don't think it's absolutely required, but the idea of invoking the kami is that you get them to understand what you want - if you can't see the target, confusion might occur. I'd allow the attempt to be made but I'd make the roll more difficult (how much would depend on the situation - if only your target is present the chance of a mistake is small, but if you try to get the kami to befuddle three specific samurai out of a group of twenty and you can't even see them expect a high likelihood of things going really, really badly for you). That's houserule territory though.

I'm a bit of two minds about this.

First off I think we should really be of the mindset that shugenja invocations are prayers and as such are immersed in rituals that contextualize when and how to properly... err... invoke them.

That means that, as a general rule, we shouldn't see them as "unfair". Court is not a sporting event, it's a life and death arena with actual lives at stake.For example, I can see court starting with a prayer session where the shugenja "bless" the courtiers, and there is absolutely no reason why courtiers and shugenja wouldn't engage in religious rituals before and in preparation for court.

Having said that some invocations are about as subtle as putting a gun to someone's face and observing on how sad it would be if they don't agree with you. You might get away with it, you may even get what you want, but sooner or later you are going to find yourself isolated and facing a wall of stone faced courtiers that are fed up with your ****, nor are they going to be kind to the zealot that keeps praying in the middle of a discussion about where to allocate the year's Miya's Blessing.

So you should probably take it in a case by case basis.

Enhancing invcations will be fine most, if not all, of the time.

Debuffs might be seen as an insult or even as a direct assault. You may get away with it, but you should be prepared to face a blood feud over it.

In regards to your second question most invocation do seem to be LoS. There are some that specifically are not, so again it is something on a case by case basis.

Well, so obviously for the Soshi ability to be useful and of note, casting in some situations has to be inappropriate. But I would also note that one of the Soshi effects is simply to increase the difficulty of Theology checks to detect or understand their invocations and channeling, so this also means you can attempt to do so without automatically being detected. Suzume has a pretty good on it, many invocations are ritual prayers and offerings - some which invoke the elemental kami, others the fortunes or ancestors, some are alchemical formulae. The simple act of a prayer may or may not draw the attention of the uninitiated, those a particularly scholarly or pious individual (or a trained shugenja) might be able note using the specific actions to invoke.

But, an important dimension is that anything done behind a fan or shoji screen is private, and cannot be brought up in public without dishonoring yourself by admitting to eavesdropping. If you mutter a quick spell behind a fan and help a friendly Courtier in distress, or perhaps hinder a political opponent, people around you can't always bring that up directly without hurting themselves (though they will certainly act on such information on their own). This might give you a measure of "polite fiction" to allow casting of certain Invocations in a court setting. If you like, throw a fireball I don't think even being a Soshi necessarily helps because the fire part sure isn't subtle or hidden from view.

There's also the possibility that it depends upon where you are, who you are, and possibly what tradition you are using for your invocation.

If you are in Kyuden Isawa, you'll probably be allowed more leeway for invoking the kami, but possibly less leeway for what invocations are appropriate: the Isawa know exactly what you're doing. Then again, trying to use the foreign traditions of meishodo there might just have you stopped entirely in the current circumstances.

On the other hand, getting permission might be more difficult in Lion lands, but you are possibly able to do something a bit more sneaky in terms of what they think you're doing.

Finally, invoking the kami in Imperial Court is done only by Seppun, or people who have been carefully vetted by the Seppun.

So much of this is dependent on the setting. I can see some places and times where it might be appropriate to invoke the kami, and many many more where it wouldn’t. And as is so often the case in Rokugan, I think it mostly depends on what the highest ranking person present thinks about it.

Invoking a prayer or blessing at many formal functions seems reasonable... especially if the player gets permission from the Daimyo/Big Wig who is Pooh bah of the meeting. You probably get to do this once...usually at the beginning. A good way to sneak in a buff spell. “Less good” to try and use something like Matsu’s Battlecry... (though if you hate long & boring meetings...😂)

Under normal circumstances I don’t think it’s approriate to cast spells at a formal meeting. “Hey what are you doing?!?” Especially if what you are doing is not in the interest of the Lord in charge. Don’t get caught! Being a Soshi here would be a boon. Other characters need something like a distraction to try to cast without being noticed. There are shuji’s that might allow an ally to set you up.

My 2 cents

11 minutes ago, Void Crane said:

There are shuji’s that might allow an ally to set you up.

Yeah, if you’re a Soshi, be sure to bring a friend with Sensational Distraction with you Otherwise, you’re not very sneaky until rank 3+...