Red

If you had to name a color to represent Japan, that color would be red... From vermilion ("shuiro" in Japanese) to darker shades, the extensive usage of red pigments comes from a long tradition and some of the origins can still be detected at Buddhist temples and Shinto shrines.

Actually, one of the esoteric meanings of the color red is that it keeps away bad spirits and diseases. That's why many gates are colored in red, and in same cases even the statues guarding the gate are also painted red, like these Nio guardians from the Shitennoji Temple, Osaka.