Two large grain varieties, Miyazaki Ootsubu and Shinshu Oosobo, and one medium grain variety, Hitachi Akisoba, were used to study the influences of sowing date, seeding rate, and sowing method on the agronomic and yield characteristics of buckwheat grown as a fall crop in Changhua area of Taiwan. Experimental results indicated that judging by the yield performance, the proper sowing time for the large grain varieties was around October 25, which was about 20 days earlier than the conventional sowing time practiced by the farmers. The most suitable seeding rate for obtaining the highest grain yield was 90 kg/ha. The seeds could be either broadcasted or sown in strip rows. For the two large grain varieties tested, Miyazaki Ootsubu outyielded Shinshu Oosoba by 28-73%.