Since it soon became obvious that the Japanese force had no air cover, the U.S. aircraft were able to set up for their attacks without fear of opposition from Japanese aircraft. U.S. bomber and torpedo aircraft arriving over the "Yamato" group—after their two-hour flight from Okinawa—were thus able to circle the Japanese ship formation just out of anti-aircraft range in order to methodically set up their attacks on the warships below. The first wave of U.S. carrier planes were spotted by a Japanese lookout on the bridge at 12:32. Two minutes later at 12:34, "Yamato" opened fire with her 460 mm main batteries. The Japanese ships stopped zigzagging and increased speed to , began taking evasive maneuvers, and opened fire with their anti-aircraft guns. "Yamato" carried almost 150 anti-aircraft guns, including her massive 460 mm main guns that fired San Shiki anti-aircraft shells. The U.S. pilots deduced that the use of San Shiki and colored gunfire meant that "Yamato's" gunners relied on visual aiming and ranging, rather than being radar directed, and as a result "were missing with great consistency" despite the storm of fire that they put up.