I'm sorry if this has been asked before, but I couldn't find the answer. On p. 14 of Dominus it describes using martial knowledge before you have it, as long as you don't use more than 50 above. On p. 15 of the GM toolkit it says only use 1/4 of MK for Low Super and 1/2 MK for Medium Super.

So, the questions I have are thus.

If I have 100 MK total, and it's a low supernatural level campaign, and I want Use of Ki, would that work?

The math: 1/4 * 100 = 25 (+15 borrowed)

Would I roll the POW check at -1 (for 10) or -2 (for 20)?

The math: 15 rounded up = 20; 15 rounded down = 10

I know I apply the modifier to my own POW, but what am I rolling the POW check against?

this is based of the old stat check system where you had to roll as low as possible where as a "-1" is applied at your result.

if i roll a 2 and i have 5 strength i would suceed by 3, if i roll a 5 with a strength of five i barely suceed and any "-1" makes me fail. a 1 being treated as a -2(+3 to sucess) and a 10 as a 13(-3).

But since I presume most people use the new system this no longer make sense and need some kind of guidance for the degree of difficulty.

So we will treat every "-1" as a +1 to the difficulty degree. In order for it to be relevant.

so in order to keep a somewhat equivalent difficulty curves we can see that a 10 on a roll with a maximum difficulty(50MK borrowed) of -5 has a end result of 18. Meaning that 18 is the value for automatic success.

In order for 18 to be the lowest automatic sucess in a worst case scenario in the new system it's difficulty needs to be 19. this would mean that the base difficulty value is 14. Now there is also a big range boost due to the +3/-3 of both extreme end roll result. since this was cut off in the new system I suggest to go somewhat in the middle by reducing the initial found base value by 1 or 2 but let's see if that necessary.

To evaluate it's impact let's say a lvl1 martial artist with 8 in power does that with only 10 borrowed MK. This would mean a difficulty of 15 as such a character with 8 in pow has 40% of succeeding at the usage of uncompleted power.This is far more then a respectable value considering the power is not even mastered yet. you're a talented guy but you're playing with fire.

so if you're using the new stat roll i would suggest as follow : base difficulty is 14 + 1 per 10 range.

If it comes to round up and down I would round up in your case making the difficulty a 16. Why ?if a game master does that he is already doing his player a favor by allowing him to try his luck using something he doesn't master yet. Don't u think it's already generous enough ?

It is plenty generous. Thank you for the help.