HN Theater @HNTheaterMonth

Here's a section of Michael Redmond's (9-dan professional Go player) commentary on the Lee Sedol vs AlphaGo matches: https://youtu.be/yCALyQRN3hw?t=3031

It's really fun to watch his commentary because he relentlessly plays "variations" — possible next moves and sequences — while waiting for the players, explaining the tradeoffs between moves and the consequences they lead to a few steps ahead in the game.

I don't know what to call "variations" but a tree search with heuristics. He does it slowly to explain it to the audience, but I have no doubt the same process runs much faster in his mind.

⬐ YeGoblynQueenne

Fast enough to evaluate a few million future positions in a few seconds? Like I say in another comment, even professional players cannot "look ahead" more than a few ply, so whatever it is they're doing "in their heads", the tree search they're reporting is not how they win games.

To clarify, you can come up with an explanation of anything that you do, or observe yourself or another person do. For example, you might explain how you hit a ball with racket in tennis or with a bat in baseball, etc, but that doesn't mean that the process you are describing is the process that your mind (let alone your brain) actually follows.

If nothing else because such a description will necessarily fudge important steps. For example, if I describe myself walking as "I put one foot in front of the other" - have I explained enough about walking that it can now be reproduced mechanically? Experience teaches that -no.

"look at that move. that's an exciting move"

https://www.youtube.com/watch?v=yCALyQRN3hw&feature=youtu.be

cf post game 3 conference commentary : https://youtu.be/qUAmTYHEyM8?t=20639

(also during the actual game with more details, but I can not find the exact time again). Edit : can not find game3 commentary but during game 4 he is coming back to it again with interesting details as for why this is a great opportunity to inspire human players : https://youtu.be/yCALyQRN3hw?t=7097

Basically, once in ancient Japan and more recently a Chinese origin player in Japan, both incredibly strong players, surprised everyone with never before seen moves that subsequently where integrated in modern game theory. The hope is that the same could happen here.

GoGameGuru just published a commentary of the game with some extra insight https://gogameguru.com/lee-sedol-defeats-alphago-masterful-c...

The author thinks that Lee Sedol was able "to force an all or nothing battle where AlphaGo’s accurate negotiating skills were largely irrelevant."

[...]

"Once White 78 was on the board, Black’s territory at the top collapsed in value."

[...]

"This was when things got weird. From 87 to 101 AlphaGo made a series of very bad moves."

"We’ve talked about AlphaGo’s ‘bad’ moves in the discussion of previous games, but this was not the same."

"In previous games, AlphaGo played ‘bad’ (slack) moves when it was already ahead. Human observers criticized these moves because there seemed to be no reason to play slackly, but AlphaGo had already calculated that these moves would lead to a safe win."

Which, I add, is something that human players also do: simplify the game and get home quickly with a win. We usually don't give up as much as AlphaGo (pride?), still it's not different.

"The bad moves AlphaGo played in game four were not at all like that. They were simply bad, and they ruined AlphaGo’s chances of recovering."

"They’re the kind of moves played by someone who forgets that their opponent also gets to respond with a move. Moves that trample over possibilities and damage one’s own position — achieving less than nothing."

And those moves unfortunately resemble what beginners play when they stubbornly cling to the hope of winning, because they don't realize the game is lost or because they didn't play enough games yet not to expect the opponent to make impossible mistakes. At pro level those mistakes are more than impossible.

Somebody asked an interesting question during the press conference about the effect of those kind of mistakes in the real world. You can hear it at https://youtu.be/yCALyQRN3hw?t=5h56m15s It's a couple of minutes because of the translation overhead.

Just in case someone wants the commentary around this move 78

https://www.youtube.com/watch?v=yCALyQRN3hw&t=11413

⬐ panic

Here's the Myungwan Kim commentary around that same move: https://www.youtube.com/watch?v=SMqjGNqfU6I&t=1h33m. He had been looking with Hajin Lee at variations involving the move beforehand (https://www.youtube.com/watch?v=SMqjGNqfU6I&t=1h28m1s), so he immediately noticed that AlphaGo made a possible error in its response.

⬐ thomasahle

But Kim also jumped a bit backwards and forward for a few moves, until he finally decided it was a mistake. It didn't seem 100% clear.

⬐ kerkeslager

Professionals are understandably hesitant to call AlphaGo's plays mistakes after the first few games, because AlphaGo had played a few moves that seemed like obvious mistakes (the eyestealing tesuji under the avalanche and the fifth line shoulder hit) but later proved to be very strong moves. Remember that when go is your career, your reputation is based partly on your ability to analyze games accurately, so calling a move a mistake and finding out later that it was strong would be a big embarrassment.

Here's the post-game conference livestream:

https://www.youtube.com/watch?v=yCALyQRN3hw

At the end, Lee asked to play white in the last match, and the Deepmind guys agreed. He feels that AlphaGo is stronger as white, so he views it as more worthwhile to play as black and beat AlphaGo.

Conference over, see you all tomorrow.

⬐ nemonemo

Lee asked to be black, because there's 7.5 points advantage for the white who follows the black, and Lee won as a white this time.

⬐ alanfalcon

Given that Lee was black in games one (due to luck of the draw) and three I expected he would be in game five as well. Perhaps the system permits loser to choose?

⬐ hatsunearu

normally the color of the 5th game is chosen by the result of the 4th game, but Lee asked to change that rule and make him black, so he can have a shot at beating AlphaGo as black.

⬐ aprescott

Is there a source of the rules for colour choice? I had thought it would be another nigiri as in 1st game. Choosing it based on the 4th game's result would imply Lee Sedol would have been given white. Since he won with white, isn't it an unfair advantage in general? For instance, if it were 2-2 after the 4th game.

⬐ CydeWeys

Are you sure? I thought I heard the commentators saying that it was randomized again for game 5, but maybe I was mistaken?

⬐ eruditely

Someone tell Lee Sedol to ask for a match extension so it's not 3-2 if he wins, and if he somehow wins the next match after this, and wins the match extension he will reclaim his lost glory, then he needs to retire asap.

He seems to have made tactical improvements to his game so it's not too much of a longshot.

⬐ itsAllTrue

No way. Good sportsmanship means not changing the rules to suit mere desires.

Agreements made before a game which has been played fairly must maintain integrity.

⬐ eruditely

Not even if both sides agree? That sounds mighty ethical to me.

⬐ greenyoda

Discussion happening here: https://news.ycombinator.com/item?id=11276798