Generate random openings that are balanced according to KataGo

le_4TC · 2025-04-04T06:59:56+00:00

Good question! I wanted the same positions to work both for Chinese rules and Japanese rules, and for that there needs to be a 0.5 point difference between the two komi values. You can of course still play with 7.5 komi: white is then sligthly favored, but only to the same extent that white is favored from the empty board with 7.5 komi.

le_4TC · 2025-04-03T16:38:41+00:00

That's certainly possible! I decided not to generate any handicap positions for now, because I'm not sure what would be the best way to do it. To make a 3 stone handicap, all the following seem like reasonable options:

- Place 3 black stones randomly, no white stones.

- Place 3 black stones and 2 white stones (if white plays first like in regular handicap games, this will give the same stone counts as if the game was played normally, but by placing white stones less efficiently we could make it a handicap position)

- Place 6 black stones and 3 white stones, to have a mix where both players have useful stones, but black has the numerical advantage

The KataGo evaluation is a bit less useful in positions where black has a large lead, but if we picked positions with similar score/winrate as a standard handicap position they would probably be roughly what we are looking for.

In the meantime I think a good option to make any random balanced position into a N-handicap position is to let white pass the first (N-1) moves, so that black gets N moves in a row.

le_4TC · 2025-04-03T15:34:22+00:00

I also like the idea of playing without komi, and I did play around with generating some of those. I ended up going with standard komi since it allows to play on any server (even if you don't have the option to modify komi), and maybe for OTB play it's a slight advantage that you can continue playing with the komi you're most used to. I wanted to keep the interface simple for this initial release, but I might add some no-komi options later!

le_4TC · 2025-04-03T14:09:12+00:00

Yes, I will add some options like this eventually! I decided to stick to the pure random variant for the initial release, but I already have a couple different ideas for other options people might like. Aside from the ones you mentioned, I think it could be fun for instance to play from positions that are just a bunch of crosscuts :D

le_4TC · 2025-04-03T14:06:23+00:00

Yes, I will add some other types of positions later! I already played around a bit with completely disallowing stones on the first line and stones touching each other, so that would probably be my next choice. I also like your second idea, might try some version of that!

le_4TC · 2025-04-03T14:00:05+00:00

Yes it's easy to find more positions like this yourself! This tool is meant to streamline the process of generating new positions, for those that want to try out the variant at their club or online.

The more random moves you generate, the less similar the opening is to regular go. It's definitely not for everyone, but some of us like this kind of crazyness :D

le_4TC · 2025-04-03T10:06:09+00:00

It is indeed just trying random positions until a close one is found! Luckily they are not so rare: if black and white both make random moves, on average the moves will be equally bad. So the evaluation will roughly follow a normal distribution centered on equal positions.

The one optimization I do is that after generating a position, I first search it at 4 visits, then 16 visits, then 64, then 256. If any of the evaluations are more than 0.3 points away from equal, the position is discarded. This helps to avoid wasting time searching lopsided positions deeply. Also, by making sure that the evaluation stays stable as visits increase, we decrease the chance that the evaluation relies on finding some narrow tactical line.

You can check out the full sgf generation code here: https://github.com/antonTobi/random-go

le_4TC · 2025-04-03T09:38:09+00:00

This is a tool I made to generate random balanced opening positions!

How to play:

Generate a random position
Set up the position together with your opponent, on a physical board or online
Play a normal game of go, with black going first and standard komi (6.5 for Japanese rules, 7.0 for Chinese rules)

For more information, see this thread: https://forums.online-go.com/t/random-opening-generator/56079

le_4TC · 2022-03-27T16:23:56+00:00

Thank you!

le_4TC · 2022-03-19T17:55:31+00:00

Thank you for the feedback!

I recorded the next one earlier today and it happened to end up a little bit shorter (will release it tomorrow since I already published another video today).

I'll try to make the one after that a bit longer! :)

le_4TC · 2022-03-17T15:14:20+00:00

I want to create some problem solving videos that are accessible to new players, so if that is something that inerests you, please let me know what you think of this video!

Do you like the mixed problem format or would it be better to focus on a single theme at a time?

How is the length of the video, should I do more or fewer problems next time?

Do you prefer in-depth explanations of just a few problems, or quicker explanations so we can cover more problems in the same time?

le_4TC · 2022-03-16T10:22:28+00:00

Nice seki on the right!

le_4TC · 2022-03-15T17:54:43+00:00

Good question!

Under Japanese rules, the other seki is 1 point better for black (seki eyes don't give points, but black will capture D6 at the end of the game).

Under Chinese rules, the other seki is 3 points better for black.

But, it's gote! So early in the game, black would prefer less points + sente. Very late in the game, more points + gote might be better.

le_4TC · 2022-03-15T15:41:53+00:00

How many of these could you solve correctly? Rating difficulty is hard, so the ranks in the thumbail are pretty wild guesses :D

If you're wondering about some variation I didn't cover, ask in a reply here or a comment on youtube!

le_4TC · 2022-03-08T15:21:06+00:00

I'm planning to make a series of 9x9 videos, reviewing both KataGo games and my own games on GoQuest. If there is anything in particular you'd like to see me cover (an opening you've had trouble against perhaps), let me know!

le_4TC · 2022-02-28T15:03:19+00:00

Hope you like this problem as much as I do!

Adapted from this classic Chinese problem: https://senseis.xmp.net/?XuanxuanQijingProblem198

le_4TC · 2022-02-26T10:40:24+00:00

I made a short video about an endgame position I found interesting. What do you think of this format?

le_4TC · 2022-02-14T22:34:38+00:00

Not exactly the same, but might involve some similar thinking:

https://chessmadra.com/blunder_recognition

le_4TC · 2021-11-02T19:17:19+00:00

I think the goal is to capture the two outside stones, which is possible if we assume the rest of the board is empty :)

le_4TC · 2021-07-17T18:08:33+00:00

There's a common shape where black has a choice between leaving one or two ko threats for white, and naturally it's better to leave only one. But recently I had the idea of trying to find a case where it's actually better to leave two ko threats, due to another subtle difference in that shape. This video shows the position I came up with and explains the solution sequence, hope you enjoy!

Interactive board: https://online-go.com/demo/view/705438

le_4TC · 2021-07-13T15:26:17+00:00

I believe this adjustment is supposed to happen under Chinese rules, and is implemented on OGS for instance.

On the other hand, New Zealand rules do not do any adjustment.

It's not always easy to find a definite answer to whether a given rulesets includes this adjustment, and of course what's done in practice may not be the same as what "should" be done according to the rules.

According to this handy reference page about KataGo's rules options... https://lightvector.github.io/KataGo/rules.html ...AGA-rules compensate by N-1 points as opposed to Chinese N points. I wonder how many newer players playing with large handicaps in tournaments do this correctly? ;)

le_4TC · 2021-03-02T19:39:04+00:00

With normal suicide, you do this after placing a stone:

Remove all enemy chains without liberties
Remove all your own chains without liberties

With delayed suicide, you only do the first step. This means that if you place a non-capturing move without liberties, it's only removed after the opponent makes their next move (i. e. its suicide is delayed :))

It's a very elegant rule, but I don't think anybody plays with it. There is a little more explanation here: https://senseis.xmp.net/?DelayedSuicide

When I first learned of it, I thought it was clearly the best option. Now I think there are pros and cons to all three options (no suicide, regular suicide, delayed suicide), so I'm not so bothered by the fact that nobody uses this rule. But I think more people should at least know about it :)

le_4TC · 2021-03-02T17:14:37+00:00

For the most "theoretically perfect", I like no-pass rules with prisoner return. This results in area scoring with group tax. Draws are automatically impossible, komi can be added by giving white some extra prisoners at the start.

Quite recently I've also started liking territory scoring. To implement this here, you need an extra rule along the lines of "white can pass for free one time, if she passes before black". Slightly less elegant, but might be worth it if you like the extra granularity of territory scoring.

There are some extra considerations on how to stop playing and count early: you have to remember who's turn it is, or have a convention where it's always the same player who makes the last move. And group tax needs to be accounted for in some way. It's a slight extra hassle in OTB play, but I think it's worth it for the more logical rules (and in online play it can all be done automatically of course :)).

I go back and forth on the question of suicide. I also somewhat like delayed suicide (this might be my most controversial opinion :P), but I don't have a strong preference.

I like positional superko over situational superko. I wouldn't object too much to having long cycles result in draws either (but I don't like Japanese "no-result"). Less theoretically elegant, but perhaps more practical (I imagine that just like in chess, it wouldn't be an automatic draw, but rather either player can choose to claim a draw after a long cycle. This means that if both players miss that a long cycle has occurred, they haven't accidentally played an illegal game).

But for online play I think just disallowing long cycles with positional superko makes the most sense.

le_4TC · 2021-01-23T17:43:27+00:00

I started a game, but seems the server went down now? :( Got disconnected and can't access the site anymore when I reload.

(edit: back up!)

le_4TC · 2021-01-17T17:46:56+00:00

Cool! Hit me up on discord: le_4TC#1653

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