Table: japan_census
Columns: rank
city
1890_census
1910_census
1920_census
1930_census
1940_census

Question: For cities with a census of 74000 in 1920, what was their census in 1890?
SQL: SELECT "1890_census" FROM japan_census WHERE "1920_census" = 74000

Question: For cities with a census of 296000 in 1940, what was their census in 1920?
SQL: SELECT "1920_census" FROM japan_census WHERE "1940_census" = 296000

Question: How many cities had a census of 400000 in 1940?
SQL: SELECT COUNT("rank") FROM japan_census WHERE "1940_census" = 400000