Board Thread:General Discussion/@comment-12301089-20131211070550/@comment-11051098-20131221153946

Stefan (Shikai - "Rust & Shatter") wrote:
 * Byakuya to Ukitake: "This man (Ichigo) has no relation to the man you're thinking of (Kayen Shiba)"  -Ichigo is, and Kayen were, members of the Shiba clan. 


 * Byakuya to Ichigo: "I shall show you the difference between us. The gap in power you could never hope to bridge. Not even if you had a thousand years of training."  -Ichigo has already surpassed Byakuya 


 * Byakuya to Ichigo: "So that's it? That little weapon is your Bankai? It looks just like a regular Zanpakutõ."  -Regardless if that was Ichigo's true Bankai or not, Yamamoto's Zanpakutõ remained much the same in it's Bankai state, so Byakuya was wrong to dismiss Ichigo in that situation. 

Well, there is a reason to all of these quotes.

Even at this point, no one in SS knows that Ichigo is the son of Isshin Shiba, and a member of the Shiba clan. Even Ichigo himself didn't know that until in this arc.

As far as Byakuya knew at the time, Ichigo was nothing but a human who gained Shinigami powers by absorbing Rukia's powers. He didn't know that Ichigo had Shinigami powers on his own.

He also didn't know how Ichigo's old Bankai worked, suppressing all of his powers into a small blade which gives him incredible speed. He discovered that during their battle on Sôkyoku Hill.

Byakuya was wrong, yes, but he didn't have much information on Ichigo at the time, so he didn't know.