Red dot on illegal move (Ko)

Hi guys.

Sometimes you have your stone killed, but you can’t kill it back in the next move. You should do a move in other place.

I think it maybe a good idea to have a red dot in the place where I can’t put my stone. (I’m not sure, but I think you had it before)

Here is what I had in my game.

19x19 end game, byo-yomi. both players are using the whole board already (always different places where fight is going)

One move and I see that my opponent made a move where I can kill his stone right away. Since this is byo-yomi now I think - “Ok, I’ll kill his stone, but I have 20 sec, let’s think where I can do the next move” I didn’t find anything good, so I decide to kill that stone in the last sec.

I think you understand what happen next. It says I can’t do so. I lost the game. Just because I didn’t mentioned that in my opponent’s last move he actually kill my stone.

In that case red dot will be vary useful. Thank you.

So you lost a game because your opponent took a ko and you forgot you couldn’t take it straight back?

I don’t mind one way or the other if OGS were to mark ko specially.

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I don’t recall ever seeing such a function. Maybe it was an optional extra? But I kind of doubt it.

Anyway, I dont think many people would support it. Go board is very beautiful in its simplicity and I do not think many people would like having it cluttered with unnecesarry dots and stuff.

The ko rule may seem a little complicated at first, but after a few games you will develop almost a subconscious physical negative response to playing an illegal move and you will never have this problem again :slight_smile:

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In a real world game I would mention that I have one stone killed.

But playing online I simply didn’t mention. Even though I have played more than 100 games already on OGS.

Again, I simply love OGS. And I think it worth to share ideas and negative experience if you have one and I’ll continue playing here in Go no matter OGS has this function or no.

Oh, I guess you mean notice instead of mention. Now I understand more. :-D. And of course all ideas are welcome. :slight_smile: And if this function was optional I am sure it would be good for some (esp. for beginners). I am afraid devs have other issues to worry about nownow though :smiley:


Yes :slight_smile:

Yes, English is not my first language. I see that “notice” fits better here :slight_smile:

absolutely makes sense. I just wanted to share my experience and some thoughts around.

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I like the idea to have some kind of mark on intersections where a Ko has just been played.

Maybe you can look on the OGS Uservoice whether such a suggestion already exists, and if not, create an entry for this?

@AlexanderLyabah, I have slightly modified the thread title, is that OK for you?

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Marking a ko would be good for new players as they tend not to notice those things, although I have to wonder if we are handicapping them with it? Cause clearly on a real board there won’t be a marker just like there is no score estimator or analyze mode. It doesn’t sound like a bad idea though.

Well, on a real board you’d always have your opponent to remind you (as I sometimes need it because I sometimes hope I only need to let some time pass to make it a not-Ko :smiley: ).

IIRC KGS also has a mark on intersections where a Ko has just been played (not that I think we should necessarily copy everything from there), I think it is really helpful.

I actually don’t know if the same applies to go but if you play an illegal move in shogi you lose the game. Also In HnG when Tsutsui played twice in a row it was his lost, since playing twice in a row is illegal(although that is a more extreme example).

Not sure and rulesets probably differ on it anyway but if I recall correctly playing an illegal move counts as a pass instead and if repeated as a forfeit.

Anyway @AlexanderLyabah (as far as I understand it) argued that in real game he would easily notice his stone being taken away while online he simply missed that his opponent also captured his stone with his move, because it simply disappears, which is kinda true I guess

EDIT: it seems in japanese rules illegal move = forfeit, while in chinese a warning is issued first and in case of retaking ko without playing a ko threat first the player loses his move.

Agreed in a real game you can see your stone in the lid of your opponents goke. Although I don’t personally think the difference would be that huge. Like I said though i’m sure the red mark would help new players see ko easier.

I don’t like the idea of cluttering the board with unnecessary markings.

This is the KO rule which will come with time. There is only 2 real rules in this game after all. Loose all your liberties and you die and the KO rule.

I believe that if you try to take the KO straight away without playing a threat it will flash a warning. Is this not sufficient for almost all cases? The OP was just unlucky that he was on his last couple of seconds of his last time period. Time management is another important idea in GO that takes some time to get used to :slight_smile:

I wouldn’t be opposed to making it an optional extra however.

This is what it is in the CGoban (KGS app) “Configure” panel:


is it checked by default?

Such markings are pretty convenient in correspondence games, though.
Personally I prefer when live game interface is modelled after physical goban while correspondence interface – after game record.


I don’t remember, but I guess I checked it a long time ago.

Well if you checked than it wasn’t checked by default…


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LOL, that’s what I wanted to say, it’s just that I am not sure.

I don’t like that idea in live games. On a real board, you would risk losing the game when making illegal move like that.

If your opponent were courteous, nothing says they couldn’t take their 5 seconds to look at the move intently before saying it is illegal.