How many of the cars from Japan weighed less than 3000?
from Japan refers to country = 'Japan'; weighed less than 3000 refers to weight < 3000
SELECT COUNT(*) FROM price AS T1 INNER JOIN production AS T2 ON T1.ID = T2.ID INNER JOIN country AS T3 ON T3.origin = T2.country INNER JOIN data AS T4 ON T4.ID = T1.ID WHERE T3.country = 'Japan' AND T4.weight < 3000