For example, Attack Rating is derived from [(2 x Intelligence) + {2 x Dexterity) + Strength + Agility - Size Class]/10.

To attack an enemy, the player chooses a target area, rolls percentile dice, adds the character's Attack Rating, and subtracts the enemy's Defense Rating and other modifiers, then checks a chart to see if the chosen target body part was successfully hit.

[1] The third edition was published in 1982 as a digest-sized box with a red cover, including six books (120 pages total).

These include: In Issue 58 of The Space Gamer December 1982), Lewis Pulsipher reviewed the second revised edition (orange cover) of Ysgarth Rules System and commented that "This is the closest I've seen to a simulation FRPG, and there's plenty of potential for additions to other systems, if you prefer [...] YRS is one of the FRP bargains of this or any year.

"[4] In Issue 16 of Sorcerer's Apprentice, Michael Stackpole thought that "While the mechanics of this system seem a tad more complex than they need to be, the imagination and detail put into the world designed for the game are worth taking a few notes from."

It's a remarkable game, recommended for advanced players with dependable calculators and a lot of patience.