On the first day, the focus of the Japanese air assault was on the Allied air bases. Mitsubishi Ki-21 "Sally"s from the 7th Hikodan bombed the airfields at Alor Star, Sungai Petani, and Butterworth. A total of 60 Allied aircraft were lost on the first day, primarily on the ground. Those Allied fighters that did manage to engage the Japanese performed adequately against the Nakajima Ki-27 "Nate". However, the appearance of ever greater numbers of Japanese fighters, including markedly superior types such as the Nakajima Ki-43 "Oscar" soon overwhelmed the Buffalo pilots, both in the air and on the ground.