I remember Ysgarth from my role playing days in the late 1970s. The game first was published in 1979. It was one of a number of fantasy rpgs that I remember we tried before finally settling on the Warhammer Fantasy Role Play.
Ysgarth has got a pretty complex system of skills and attributes, but action is resolved on a simple d100 (that is, you roll 2d10s and read them as separate decimals)