So, I just watched Daiei's Great Yokai War: Spook Warfare. I recommend this movie to anyone who likes Japan mythology and tokutatsu. The film got a remake in 2000, by Kawadako or what ever company owns Gamera. They make references to Gamera and even Gegege no Kitaro, which got a live action film the same year. I HIGHLY recommend them. 
Kappa 1968

1968 Kappa