Hugely agree with your response. Just to add slightly to that, I think the fact that Facebook had a quite similar Go AI in the works (just without self play rei

Hugely agree with your response. Just to add slightly to that, I think the fact that Facebook had a quite similar Go AI in the works (just without self play reinforcement learning) in the works is an indicator of how clear this research direction was. The complexity of Google's solution (2 neural nets and a fast evaluation function, plus other small details?) really indicates to me a lot of manual engineering and iteration went into this. So it is not really an indicator of cool new theoretical breakthroughs, but an indication that applied engineering to make use of known techniques can achieve great things.