ELF OpenGo weirdness

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I am getting regular options on a first test.

Update: now I see it too! Although C6 takes over if I wait long enough.


Posted to Reddit for further discussion: https://www.reddit.com/r/baduk/comments/bge15j/new_fuseki_leelazero_v017_with_elf_opengo_v2/

FWIW, after wQ4, the only moves AlphaGo Teach considers for black are C6 (winrate for white 53.6 %) and P17.

“Best” variation after bC6: https://online-go.com/review/388633

Feels highly unusual in its own right. AGT gives it 52.5 % for white.

People seem to be confused because you played white Q4, not R4 as in @mark5000 's original example (I am too).

I reproduced the 3-4 armpit hit and micro enclosure with unmodified Lizzie 0.6 and ELF converted weights. ELF started choosing them early within a few thousand playouts. I’ll check native ELF next.

EDIT: I reproduced them with native ELF too. This is using just 3200 playouts.

So I’m back to square one: these moves are network preferences of the strongest freely available AI at the moment. I realize it’s not an oracle, but it’s also, like, 14 dan, so I’m trying very hard to make sense of its moves.

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Here’s another position from 1. r16 d17 where ELF would play 2. c16 even at kind of low playouts. It does it again in the LR corner (different order), encloses micro in the UR corner, kicks the high approach in the LL corner, then goes all AlphaGo with move 25. New meta or neural network gone wild? You decide.

EDIT: after 400k playouts the winrate gradually drops 4% and ELF starts to prefer 2. d3 without the c16/c17 exchange. It’ll still play it afterwards, however.

EDIT 2: 1 million playouts. c16 became the top choice again.


My bad… Shouldn’t be doing stuff like that at 2 in the morning. blushes

These variations are highly fascinating to this 12k. I keep adding them to the review that I posted on Reddit, I hope you don’t mind. Thank you for your work, mark5000 :slight_smile:


This is truly interesting, but I am not really surprised. You can think about the fuseki preferences for these strong AI as numerical solutions to the game of Go. At points where the best move more obvious, the AIs will agree more often, but when the best move is uncertain, like the opening where many points have close to the same value, it’s very reasonable that the solution will have more variance. The fundamental method behind LeelaZero does not produce the solution to Go (as a mathematical problem) but only a solution. It’s my personal belief that there are multiple (in the dozens) of different fuseki patterns/theories that are nearly equal. The difference between them probably can only be determined through theoretical analysis. Unfortunately, it seems that humans lack the requisite theoretical tools to undertake such a task.


I think you’re on to something there. I started this topic because OpenGo v2 differs so much from predecessor AI such as AlphaGo, Fine Art, PhoenixGo, LeelaZero, OpenGo v1, Minigo, and Golaxy. I wondered how the “solutions” can all be valid. Take Minigo v17 0961’s output for example:

This is so much more conventional to my eyes. But OpenGo v2 wouldn’t be caught dead playing 4-4 points at >10k playouts. Two star points to OpenGo v2 is an 11% mistake. This means one of two things: (1) OpenGo v2 knows something other AI doesn’t, or (2) OpenGo v2 is kind of badly misjudging the above positions. Right now I’m leaning towards door number 2.

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Could it be that you are challenging the AI with unconventional opening patterns for which it has little knowledge? One of your examples involves a 3-3 point, and the other opens with four 3-4 points.

I just started an ELF-LZ game on Sabaki, and so far it looks much more conventional (well, from an AI perspective).


Yes, that’s what I think is happening. ELF was trained on 800 playouts a move. At 800 playouts, it opens with a 4-4 point and White replies in kind. If given more playouts, it eventually switches White’s reply to a 3-4 point, which it considers better, and will eventually switch Black’s move to a 3-4 point, too. It’s from that starting position that I ran the above tests and noticed weird moves.

My takeaway is that more playouts isn’t necessarily better for ELF v2, and it can be unreliable in positions it wouldn’t ordinarily choose, even if that position is one 3-4 point and nothing else on the board. It’s a little disappointing.


FWIW the finished game. ELF v2 (black) wins by 1.5 point. An epic game with two large ko fights towards the end (each ko fight lasts more than 70 moves…).

I ran another game with ELF as white and 5.5 komi. LZ resigned. I am now very tempted to switch to ELF for game analysis, despite the weird opening analysis showed by @mark5000.


Is there any way to combine them, so you get suggestions from both ELF and LZ at the same time? Something like rating the best moves for both AI and then choose the move that both consider to be good. Surely two overwhelmingly strong AI are even stronger than each of them individually, right?

If you want to show the suggestions of both networks at the same time on one Goban, this would be possible. I don’t know of any toolchain to do it through.

If you want to combine the two to a stronger AI, there are several problems. You can use both to explore the game tree by exploring the best moves of both AIs. But if it comes to decide which move is the most promising of the explored moves, you have to come up with a decision mechanism based on two estimated win rates (one for each AI) of which you don’t know which is more accurate.

  1. You could go for the best move of the stronger net. This would probably result in a weaker AI because you spent some playouts for branches with lower win probability (following suggestions of the weaker AI which turned out to be not promissing in the eyes of the stronger one)

  2. You combine both winrates to a combined winrate.

    1. One possibility would be to choose always the higher winrate, hoping the lower value was wrong.
    2. You use the lower winrate, just to be save. Here you follow the more conservative estimation. You wouldn’t get the best move, but only a good move, both AIs can agree on to be not too bad.
    3. You walk some middle ground by averaging both winrates with any function you think would work best, but this wouldn’t lead to better moves, too.

    The problem with combining 2 AIs is that they aren’t good at reasoning. They tell you this move is good and that move is bad, but they cannot tell you why they think so. Even less they have a way to convince the other AI why they think this possition is good/bad.

    Even humans could have a hard time to find a common ground (This move is the best because it increases our influence/territory). Just imagine combining two human go players. Like the two AIs they have to use the same brain (the AIs share the same CPU, RAM, GPU, …). Neither of the combined humans can play at their full potential because some thinking time goes to the other.

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Golois bot, apparently using ELF v2 weights, played diagonal approach in a Fuzhao Go AI tournament game today:



I’m not sure ELF v2 weights are actually stronger than LZ’s own latest networks.

I played out the second position to the end with KataGo on ZBaduk. At the given position, it sees black as having 35 % (vs just 29 % by LeeLa Zero).

I always played KataGo’s favourite move once it had at least 12,000 playouts and was preferred to its second-favourite move by at least 0.3 pp decision and 0.3 pp winrate (which often meant much higher playouts, up to 1.7 million in one case).

ZBaduk screenshot: https://i.ibb.co/Xtmyt2z/Screen-Shot-2020-01-14-at-10-10-12-AM.png

Do current ELF OpenGo v2 weights still produce similarly weird fuseki?


Anton Christenson, EGF 3d did a 65-minute YouTube review of this game!

I’ve added all of his (commented) variations, plus more KataGo variations, to the OGS review as well: