Ichigo taking on "Several Captain level opponents"

[Insipidipity]

I was just wondering what Byakuya meant by this(Before he was about to kill Ichigo). Renji hadn't reached Bankai by that time, Ikkaku is 3rd seat, Jidanbou was even weaker. The only Captain level opponent he ever really took on before Byakuya was Kenpachi(and blocking 2 hits from Gin, which wouldn't really count as taking him on). Several usually means 3 or 4, so does he mean he considers Renji or Ikkaku captain level even without bankai?

[Khemical]

May have just been the way it was translated, as far as Byakuya knows Renji may have had ban kai when he fought Ichigo, Byakuya was shocked when Renji used it. He took out Zaraki (double KO) and 3 Vice Captains without any difficulty within seconds, all in front of Byakuya as well. My guess is when he said "captain-level" he was reffering to vice captains also. It seems logical anyway, like you said, several is usually more than 2 and Ichigo took out 4 Vice Captains and a Captain (Ikkaku really should be considered VC anyway).

[Tsukiyomi]

Wasn't the lunar translation in the anime "people with the title of captain", I'm not sure how accurate that is, but the way it was said would probably include VC-level opponents.

Its also possible that Byakuya assumed Ichigo killed Aizen since he was the only Ryoka with enough power to match a captain.

[gumzz]

maybe they meant you have taken on people with the skill of captains 7 times?