Toshio Kawamoto was born in the Kanto (Tokyo+) area of Japan, the first of seven children to bonsai master Tokichi Kawamoto. He graduated from Azabu High School and continue studying and assisting his father. At his father's death in 1960, Toshio took over the family's nursery Meiju-En, establish the Nippon Bonsai-Saikei Institute, and forming the Nippon Saikei Association.
After WWII, bonsai had still been a creative pastime of only a small number of wealthy enthusiasts and the sons of bonsai specialists. Toshio would feel that this could become a popular hobby that anyone could enjoy, regardless of social or economic class. He combined the best of group plantings and rock-grown bonsai, which were increasing in popularity at the time. Due to shortages of suitable mature material for bonsai, young specimens would be utilized by this author and lecturer to successfully depict sections of natural scenery.
These containerised living landscapes of trees, rocks and mosses would be known with the name of Saikei. His first English-language book would be Bonsai-Saikei (1963), followed by Saikei: Living Landscapes in Miniature four years later. He would write and illustrate articles on Saikei each month in a series published in Bonsai World magazine.
Saikei has a huge following across the world it was for the benefit of the interest in Saikei that the International Saikei Association was formed.