Even before Japan's official delegation to the latest annual meeting of the Asian Development Bank (ADB), held last week in Delhi, began arriving back in Tokyo, another gathering of some several thousand business, government, and social sector leaders — from Bill Gates to Tony Blair and Rupert Murdoch — had concluded here on the other side of the Pacific Ocean.

Focused on finding solutions to some of the world's biggest challenges, from finance to biomedical research, the most recent Milken Institute Global Conference understandably featured frequent mention of Asia given the region's and particularly China's growing importance and economic rise. With the advent of "Abenomics," Japan too was back as a topic of discussion.

There was little talk, though, of the Japanese-led Asian Development Bank (ADB) and its efforts to grow economies and fight poverty. That's understandable, given the relatively small size of the ADB when contrasted with private sector capital flows and the size of Asia's largest economies. And therein remains the challenge, and the opportunity, for the latest ADB president to be elevated from the ranks of Japan's Ministry of Finance: how to ensure the multilateral development bank remains relevant at a time when Asia is changing faster than the ADB.