About the shape - Santoku means 'Three Virtues' or 'To solve Three Problems'. The three virtues are meat, fish and vegetables, or slicing, dicing and mincing depending on your interpretation. This means that the Santoku is an all-around knife, suitable for the amateur home cook and the professional chef alike. The heigh means good clearance for big hands, while the relatively short blade can be wielded by anyone.
About Yoshida Hamono - The first generation of the Yoshida family was, like many, a swordsmith. After WWII, they decided to open a small workshop to produce knives and other steel tools, and in 1971 they expanded to a large scale production to meet a growing demand from all over Japan. They invested early in modern machinery that made large-scale production possible, which is one of the reasons why they have the ability to clad their own steel, rather than buying it pre-laminated. Because Saga is not a major production center for knives and there are not many other craftsmen, they have built a facility that can handle the knife making process entirely from start to finish.
In 2017 when the ZDP-189 became first available, Osamu Yoshida quickly purchased the steel and tried it out. He was amazed by how insanely sharp the steel could get and how long it would keep its edge, so he started making kitchen knives using this super steel. Despite being hard steel to deal with, he feels a great sense of accomplishment when he forges with it compared to other steels.