Board Thread:Questions and Answers/@comment-5775318-20130223175459/@comment-11051098-20140413134513

While fighting Ichigo right after he entered SS, Yhwach said "it was a mistake to send a pure Quincy to stop you". From that I understood that it was the reishi in Quilge's jail that caused the "memories" in Ichigo's reiatsu to awaken.

In other words, it suggests he was a non-Quincy when he was trapped in it, but became a Quincy while being trapped due to his powers being awakened, eventually making him capable to break free.