All players play to marginally beat their opponent. Playing too aggressively when you're in the lead is "losing a won game" because it gives opportunities for y

All players play to marginally beat their opponent. Playing too aggressively when you're in the lead is "losing a won game" because it gives opportunities for your opponent to create turnarounds. In the end of a well-played game the losing player will find that they perhaps get more points than they expect, but each time they win a tradeoff with a slight margin the position on the board becomes much more solid and fixed than it ought to be. A 10 point lead with a large variance consolidates toward an unfaltering 1/2 point lead. Indeed, commentary on Master (P)s games seemed to suggest this was exactly how endgames went. Early in the game, confidence in winning is usually correlated exactly with point margin... but at the same time, score in the early parts of the game is very hard to estimate. It's repeatedly noted that AlphaGo plays a very "influence oriented" game which means that it eschews confidently having many points for having lots of "power" on the board which will later translate to points. So, all together I'd say that AlphaGo plays very well here and doesn't have too much of an obvious computational bias. The one true oddity is once AlphaGo's internal win probability reaches 100% it starts playing idiotic moves. The reason is simple: it's just searching for moves which have the highest expected win rate and at this point nothing it can do is bad. It won't lose points or anything, but instead just plays moves that are obviously pointless.