Foremost are the so-called Shibuya three (their head offices are in the Shibuya district): Chiyoda, Japan's eighth-biggest life company, and Toho and Nippon Dantai, two middling-sized firms.
We have forgotten that regardless of the target market, the key decision-maker, whether he or she is a financial adviser, a hospital administrator, a CEO, a mom buying a toy for her child, or the head of a large contractor for the military, is first and foremost a human.