Scoring question: last ko not connected

I just finished this game (Japanese rules): Jon Ko vs. yy2081

My opponent and me were fighting the last ko, but I couldn’t find another ko threat, so I passed, my opponent passed too and I won by 0.5, but the AI says white is ahead by 0.5 before passing. So I think the auto-scorer counted A16 as a black capture. The stone is transparent, but not marked with a black square.

So does anyone know if the result is correct, or what the correct result should be?


I always knew beginners tend to pass prematurely, but I’ll now have to expand my definition of beginners to include 1k. :smiley:

About scoring: no idea. In Japanese rules you can only use pass as a ko threat in hypothetical game continuation, so the single white stone is dead? Sounds wrong, probably doesn’t apply here.

This shows the game should really be over after 3 passes, not 2. Black never claimed that they had no idea how to gain more points here, only that at that one moment that plan was not allowed.


Sounds right to me: white shouldn’t have passed, but should’ve connected the single stone. Now Black can legitimately claim that the stone is dead, since in the hypothetical continuation it is not allowed to make non-local ko threats, if I remember correctly. So white can’t actually defend the ko.


Couldn’t you just resume the game and take the ko if white fails to connect?

Also, on move 302 I would have played a neutral point at G11 or H11 and keep playing neutral points as ko threats before passing, just to make it harder for white to get away with this sort of trickery.

1 Like

I watch lots of games, especially at the DDK level, and I can tell you that stones in a ko are very frequently marked as your was, and I am fairly sure they are counted as captured. I have often wondered whether this is right. Sometimes they are in hanging cuts and the autoscore does not score the player’s territory behind it (i.e., it treats it as an unclosed border). I have posted several examples of this in the threads dealing with the scoring system problems.


@Vsotvep is correct. White should have connected that ko before passing. As it stands, the scoring is correct since Black can capture in the hypothetical continuation of play.

I don’t think it is both players lose, since White could safely ask for a resume, giving Black the first play and take the ko, since White appears to be ko master, having enough ko threat to win that ko back.

Before the modern rules, this type of ko situation created a scoring dispute among pros, which likely influenced the modern formulation of the rules.


Ultimately, the game was scored okay, assuming that White ko stone was counted as dead.

However, strategically speaking, White should have resumed and won/connected that ko.

1 Like

That’s probably what I would’ve done if A17 had been marked as white territory. Now it seems white tricked themselves by not connecting.

Very interesting, I didn’t know about that before.

That doesn’t sound quite right. You can pass whenever you want. If you opponent decides not to connect a ko, maybe they can’t with a shortage of liberties, I’m pretty sure you can recapture the ko. I’ve even seen sitatuions in Cho U’s app on 4x4 go where you pass to win a ko. There’s a section on winning ko by passing.

Though maybe I’m not reading the sentence correctly.

I don’t see any contradiction between what you say and what I meant. :slight_smile:

Right I suppose I could read it in two ways:

  1. as in passing isn’t a ko threat, unless you’re in hypothetical play.

or lets say

  1. passing is the only valid ko threat in hypothetical play. (says nothing about the normal game)
1 Like