If it is what I think it is, then it uses advanced pen settings that were not available in SAI I. There is a brush called Water Blur in SAI II and it's in its own category in the drop-down menu, below the other two.
Either look at the bottom of the list or, if you have SAI I, there is nothing to find.
Yes, I found that and this is super close to what I want or maybe it even is the same thing! I just isnt doing it right or something! mine is more sharp edged compare to that picture I show u there, so I wondered if its the same thing ... coz everything seemed similar apart from the round edges in the picture