For what we know, RAW, a black blade intelligent item follows it's own rules (and you can find this rules in the bladebound archetype).
For example, in regard of skills, the entry states:
Languages and Skills: A black blade starts with Common as a language. As the black blade increases in Intelligence, it manifests knowledge of languages and arcane lore. Upon reaching an Intelligence of 12, it gains a bonus language of the GM’s choice, and gains 1 rank in Knowledge (arcana). Each time the sword gains a bonus to Intelligence, it gains another language and another rank in Knowledge (arcana).
So, for sure, a black blade possess knowledge(arcana) as a skill...but the other?
I will say that, knowledge(arcana) is the only skill a black blade possess.
The reason is, rule as written, you can't upgrade your sword with crafting feats as this FAQ clearly explains:
Can I use Craft Magic Arms and Armor to increase my blade’s enhancement bonus?
No, nor can you use that feat to add other properties (such as flaming) to the black blade. You can use your arcane pool to temporarily add abilities to your black blade.
For what I know the only way to give skill ranks to a magic item is this:
36–45 | Item has 5 ranks in one skill* | +2,500 gp | +1
and you can choose only an intelligence, wisdom or charisma skill (for obvious reasons since a black blade have not a strenght, dexterity or constitution score).
The only catch I can find is explained in the previous FAQ: you can upgrade your black blade with your arcane pool so.
In regard of using skills other than knowledge(arcana)..if the skill is an intelligence, wisdom or charisma skill yes, the item can use that skill since, with very few exception, even only trained skills can be used to a certain extent without any training at all.
Link to Bladebound: Blackblade skills and faq source |
Link to intelligent item: Intelligent items table of powers source