Japanese admirals were really loath to adapt radars. Japan wasn't particularly behind in the radar tech, but the admirals thought the negative side, the radar emissions revealing the fleet's location, was worse than the positive side, being able to exactly and fast measure the distance to the targets. The Japanese navy did install some early warning radars for detecting enemy aircrafts, but that was pretty much it, for a long time. It's often said the Japanese sailors were really good at gauging distances using optical range finders and other means, but obviously they couldn't beat the American radars.