In order to make the rules for building relationships definite, I need to start attaching numbers to it. The best place to start is with the strength of relationships, since everything will develop from there.
A strong relationship is, let us say, a score of 6. This allows for a lot of differentiation between relationships; the average result of keeping 2 dice is only one higher than the minimum possible result from keeping 6. Of course, relationships can be even stronger than that, but we will assume that 6 is a normal maximum, and probably the default value for a father’s relationship with his children.
When you are building a relationship, you can try new positive actions at any time. Even if they do not improve the relationship, they will not make things worse, and I want to retain that in the game. The only limit is time. For a rough approximation, suppose that you are keeping the same number of dice for both the action and the character’s reaction to it. The maximum possible roll is 6N, where N is the number of dice you are keeping, and the maximum possible reaction total is 12N, because it is doubled. In order to improve the total, the difficulty must be no higher than 6N-1. If you roll the maximum possible result on the reaction total, the difficulty for the next action roll is 6N-1 if the running total, R, is such that R-(12N-R)=6N-1, or 2R-12N=6N-1, or 2R=18N-1. So, the highest possible total is 9 times the number of dice you are keeping.
This is too hard to reach, however, so we should set things a bit lower. 8 times the number of dice would be reasonable. Let us say that you need to be keeping 6 dice to build a really strong relationship, and set the difficulty at 8 times the level of relationship at which you are aiming.
How would we get that many dice? First, there’s the question of creating the action. We could use the same difficulty scale as the matsuri, with a base of one, so that just doing something generic lets you keep one die, and adding personalisation lets you keep more. In that case, getting to keep six dice would have a conception cost of 13 and a difficulty of 32. That should be just about possible for people keeping three dice to devise the action, because they can get the difficulty down to 27, and it’s reasonable for people with four. That means that, according to the rules, people who are decent but not incredible can create the actions that let them build a really good relationship. This is reasonable; building good relationships is not the province of an elite few in real life.
What about making the action appropriate to the character? That brings us back to the question of investigation and discovery, and so needs to be the subject of a different post. However, we do know that getting six dice should be just possible for people keeping three dice, and a reasonable target for people keeping four, again because most people can build good relationships. That will help me to fix the numbers.