User blog comment:Northstar1012/Time to fill the ranks/@comment-1853786-20100621104259

Well the three ways to become captain if memory serves me right, is the Proficiency Exam, kill the former captain (wait a minute Hisagi killed Tôsen) or get like 7 captain recommendations and be recognised by at least 3-4 of the remaining captains.

So Hisagi may have filled one of those criteria though he had help from Sajin, needed 200 witnesses and the fact that Tôsen defected may be an obstacle.

Anyway, Hisagi would make the best captain out of the current Lieutenants.