How has Japan's agriculture changed since World War II?

The number of people engaged in agriculture was 26.8% of the working population in 1960, but dropped to 4% by 2003.
The arable land area was also reduced by 22%.
However, productivity showed substantial growth due to improvements in breeding, cultivation technology, utilization of chemical fertilizers and insecticides, and automation of production processes.
The postwar government took measures to protect the farmer by enforcing the Food Law and price control laws for produce such as beef and sugar, which resulted in a loss of international competitiveness for Japanese farm produce.
Consequently, agricultual products with lower production efficiency have been weeded out in competition with imported products, and the self-sufficiency rate of Japan dropped dramatically.
The self-sufficiency rate of vegetables. which was 100% in 1965, dwindled to 83% by 2002.
The rate for fruits was reduced to 44% by 2002 from 100% in 1960.
Only 13% of flour and 7% of soybeans are produced domestically.
This shows that it is virtually impossible for Japan to feed itself without imports.