Few days ago I've stumbled across such question: is Unmei ranged attack a base ability? I wanted to use Denhei's Snake ability on Unmei and my opponent stated to me, that this is not a base ability since it's granted by trait. As far as I know (which may not be accurate) base abilities are those printed on card, and this RA, even tho granted by trait, is printed on Unmei.
Denhei's Snake: Open: Target a Personality: He is bitten. His base abilities may not be used.
vs.
Unmei While Unmei has Samurai or Shugenja, it has +3F and "Battle: Bow Unmei: Ranged 5 Attack."