Complementary Skills

The phrase complementary skills has appeared in several GURPS books over the years.
==2008 in DF==
It was first used January 2008 Dungeon Fantasy 2: Dungeons pg 11 which introduced rules called With a Little Help From My Friends allowing a benefit from "same skill or complementary skills".
The initial implication meaning the complement was not the same skill, but that complement did not refer entirely to the category capable of benefiting.
The initial focus was on assistants in real-time, as well.
==2008 in Action==
Soon after in October 2008 it appeared in Action 2 Exploits on page 5.
==others==
After The End 2: The New World page 31
Pyramid 3/70 Ten For Ten
==2011 in SE==
Complementary Skills in October 2011 were rules for Skills interaction on page 21 of Social Engineering were added, presumably based on this. It made some changes:
*complement not simply refers to the relationship towards the benefitted skill, not whether or not it was the same or different
*besides helpers, someone could provide a complement roll to their own roll, such as Writing your own speech for Public Speaking
The paired skill that they can potentially benefit on a success (or penalize on a failure) is now called a "master skill" or "primary skill"
In some cases, a Quick Contest can be rolled between complementary skills. The difference there is that winners of the contest never suffer a penalty (even if they 'failed by less') while losers of the contest never enjoy bonuses (even if they 'succeeded by less')
Social Engineering added a new restriction to same-skill complements which was absent in DF:
*complementary skill can be the same as the primary skill, but only if it’s used in a meaningfully different way.
==addition to Basic Set==
rumored to be present on page 206 as of the 7th printing
Category:Rules