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A new skill classification: Constrained.
Everyone already knows about the Occupational, Everyman, Normal, and Restricted classifications. To further alienate a skill from certain cultures, societies, races, etc., I came up with the idea of a Constrained skill classification.
If a skill is designated as Constrained, for every three ranks developed, the character gains only one rank. Character only gains one skill rank for each complete set of three ranks.
This came about when a friend GM was running a largely desert planet (had a single ocean with about 9% of planet's surface). With the culture of humans on the opposite side of the planet, he commented, "I wish I could make the idea and skill of swimming more alien to these people." I then suggested to make the skill like Restricted, but 3:1 instead of 2:1.
Just thought I'd throw the idea out here.
rmfr