I purchased the
LEGENDARY MONSTER MAKER: KEIZO MURASE book a few months back (More info can be found at this link on August Ragone's blog:
http://augustragone.blogspot.jp/2015/08 ... 6.html?m=1) which has numerous rare, never before seen photos from Murase's career, spanning from Showa to Heisei eras.
One particularly interesting and rare photo that stands out is a
blue King Ghidorah still:

My Japanese girlfriend translated to text caption. According to her, it is said in Japanese folklore that Yamata no Orochi was a greenish color. Drawing inspiration from Yamata no Orochi, they initially decided to go with a blu-ish color for KG(For those who are not familiar with Japanese culture, older Japanese texts, writings, and literature have always blurred the lines between the colors "blue" and "gree"n, with green often being lumped into "blue". For example, green traffic lights are often referred to as "blue" over here, and and Haiku poet Basho often described "the blue grass and blue trees" of spring. There was no real distinction between blue and green until crayola/crayons started appearing in the country in the early 1900s...very strange cultural tidbit.