Short answers, pulled from the story.
Kanagawa Prefecture had a population of 9,221,129 as of the 1st of April 2022, making it the second-most populous prefecture in Japan. It became the second most populous prefecture in 2006, rising from fifteenth place in 1945 when its population was about 1.9 million.
Yokohama is the capital and largest city of Kanagawa Prefecture. It is also the second-largest city in Japan and serves as the location of the largest trading port in the country.
Kamakura was the de facto capital and largest city of Japan from 1185 to 1333, serving as the seat of the Kamakura shogunate. During the 1923 Great Kanto earthquake, the combined death toll in Kamakura from earthquake, tsunami, and fire exceeded 2,000 people.
Commodore Matthew Perry landed in Kanagawa in 1853 and 1854 and signed the Convention of Kanagawa there, forcing Japanese ports open to the United States. Following that agreement and further foreign pressure, Yokohama was opened to foreign traders in 1859 and eventually became Japan's largest trading port.
The epicentre of the 1923 Great Kanto earthquake was beneath Izu Oshima island in Sagami Bay, and it devastated Yokohama and the surrounding region. At Odawara, ninety percent of buildings collapsed immediately, and at Manazuru Point the sea receded as much as 400 metres before surging back in a large wave.
Nissan Stadium in Yokohama was the final venue of the 2002 FIFA World Cup and hosted the FIFA Club World Cup from 2005 to 2007 and the 2019 Rugby World Cup. The Enoshima Yacht Course and Lake Sagami hosted events at the 1964 Summer Olympics, and the Yokohama Cultural Gymnasium served as a volleyball venue at those same Games.