I got to work this weekend and made some new large stacking serving platters with mishima decoration. I like the mishima process A LOT! I used to carve or stamp of course, but wait to fill in color in the bisque stage. I like this more refined process - though it can be tricky.
I used an exacto knife; I can see why it is both the best and not-so-best tool for the job - it's hard to "draw", to turn corners, to get a rounded off line. But, by far, it is the best line quality.
I usually use a pin tool, porcupine quill. I also tried the speedball pen recommended by Molly and wasn't that into that. I prefer the look of the exacto.
Also, the tip about using natural sponges vs. commercial is dead on as well. It's time consuming - but SO MUCH FUN!!
p.s. sorry for the craptastic photos!