abstract: OBC is a condition introduced by Cao and Hamilton which generalizes bisectional curvature. Following Siu-Yau, we will describe an elliptic proof showing that a compact positive OBC Kahler manifold is biholomorphic to CPn which compliments parabolic proofs by X.X. Chen and Wilking. Positive OBC is preserved by Kahler Ricci flow and also by Tian-Zhu Kahler Ricci flow with positive OBC will converge to the Kahler Ricci soliton, CPn.