9.0.4 SKILL SPECIALIZATIONS
Some skills "branch" into specializations, which means after mastering
the basic skill you must take a specialization of that skill in order to
train further. Most skills and specializations on the skillweb are
restricted according to archetype and more guild. Once you master the
basic skill, you cannot train in that skill further, so must choose a
specialization and train in that specialization.
For example, only the mage archetype can take the Elementalism skill and
only mages in the Aquamancer Guild can take the Aquamancy specialization.
After mastering elementalism, the mage cannot train in it further
and instead would choose and then train in Aquamancy.
Some archetypes and guilds allow a choice among several specializations.
For example, any who follow the knight archetype can choose to specialize
in either the Blademaster or Bonecrusher branch of Knighthood.