What are the mechanics for creating a matsuri? Creating the baseline matsuri doesn’t need any mechanics at all; the shinshoku just copies the norito out of a book and does the basics. The mechanics, then, are for improving a matsuri beyond the baseline.
A baseline matsuri provides 1 shin’i, no dice to roll to determine whether the request is answered, and makes 1 request. It should be fairly easy to improve this, so that even a novice persona can create a better matsuri. So, personae who are keeping 1 die should be able to make a slightly better matsuri. For these personae, the maximum possible conception roll is 6, while the highest difficulty they can possibly meet during creation is 12 (because the assessment total is doubled). However, a difficulty over 9 is likely to be very difficult.
To provide a trade-off between quality and difficulty, I’m going to try the following mechanic. Each bonus has a minimum conception level, and a base difficulty. If a player chooses a bonus, she subtracts the minimum conception level from her conception total, and if she has any conception total left, she may subtract that from the difficulty. If the total is high enough, she may put more bonuses in, but that increases the difficulty. I’ll look at detailed rules for that later in this post, after deciding on the basic case.
So, to make things possible, the conception cost for a one-step improvement should be 1, with a base difficulty of 12. That means that someone keeping a single die can always come up with an idea that is better than the baseline matsuri, but it might be hard to implement it. A good conception roll could bring the creation difficulty down as low as 7, which requires at least one round of revision, but should be fairly easy to achieve. A 1-step improvement is one of the following: 1 additional shin’i or 1 additional die to roll to determine whether the request is answered. A matsuri that can make two requests is more than a one-step improvement.
A basic matsuri has two elements that can be varied: the norito, and the mikë. This means that a minimally skilled persona can, with a bit of time, create a matsuri that provides 2 dice to roll when deciding whether the kami responds, because she can get 1 additional die from the norito, and 1 more additional die from the mikë. Alternatively, the matsuri could provide 3 shin’i, but at the moment there is no reason why the personae would want to do that. Needless to say, there will be.
What about a 2-step improvement? This should be just possible for personae keeping a single die, if they are very lucky, and quite easy for personae keeping two dice. A conception cost of 3, and a base difficulty of 15, meets that requirement. A conception roll of 6 means that the difficulty can be brought down to 12, which is just barely possible. Personae keeping two dice, however, will often bring the difficulty down under 12, which means that they could create the element without any revision.
So, what about 3 steps? A conception cost of 6 and a base difficulty of 18 would make an easy pattern. This should be straightforward for personae keeping two dice, and easy for personae keeping three. It is, however, impossible for personae keeping one die. They might be able to have the idea, just, but the difficulty is out of reach. It might be better to step the conception cost up a bit higher, however, to make it impossible for the weakest characters to even think of this. A conception cost of 7 has that effect. This is average for someone rolling and keeping two dice.
This provides a good guideline for the conception cost. Every additional die kept should make two new conception levels possible. That would mean a conception cost of 10 for 4 steps, and 13 for 5. A pattern of starting at 1, and adding three for every additional step, works well, but it means that the base difficulties need to be revised to keep a 2-step improvement barely possible for single die personae, as they will only be able to reduce the base difficulty by two points.
A simple analogy with the conception cost would be to start at 8, and add 6 for every additional step. Thus, a 1-step improvement would have a conception cost of 1, and a difficulty of 8. This is well within the capacity of personae with a single die to keep. A 2-step improvement has a conception cost of 4, and a difficulty of 14. This is just possible for personae with a single die, and fairly easy for personae with 2. A 3-step improvement has a conception cost of 7, and a difficulty of 20. This should be possible for personae keeping 2 dice, but it is impossible for personae who only keep 1. A 4-step improvement has a conception cost of 10, and a difficulty of 26. This is hard for personae with 2 dice to keep, but straightforward for those with 3.
This pattern will do for a first draft for norito and mikë, but kagura is a little different, and will be the topic of the next post.