I am playing a Bladebound Magus in a campaign with very quick level advancement, necessitating frequent recalculation of my stats. The only part of my character advancement that's confusing me is calculating my Black Blade's skill ranks. From the PFSRD:
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). [Empahsis mine]
The wording of the second sentence is the issue and I feel as if I may be aproaching my advancement incorrectly. Does the way the entry is worded mean every time my Blade's INT score increases it gains another skill rank and language (ie. from 12 to 13 with no increase in modifier)? Or every time its INT modifier increases (ie. from 13 to 14 and from a modifier of +1 to +2)?