That’s right, heavenly blue, that Kalafina song released back in August. I’ve heard nothing about Kalafina planning to shoot a PV for it, so this is really unexpected.
So far, only a short version of the heavenly blue PV is available, and it’s blocked for users outside of Japan. It’s an exclusive video hosted by Japanese entertainment site GyaO! from 17th to 23rd October. I hope it’ll be more widely available after this period. In the meantime, if you have a Japanese IP, you can watch it over here.