Did this guy cheat?

[chef]

How did this guy win? I was demolishing him and then when we were counting he somehow ended up with +4.5. The stones in the upper right corner weren't picked, but when I pressed done, they were. I do'nt get how that happened.

I played black

[Krama]

Pay more attention on marking the stones.

[emerus]

From downloading the SGF, it definitely doesn't look like he cheated. One or (more likely) both of you made mistakes while scoring. The result is seki and the proper way to score it in this position is to mark the t19 stone as dead and then it is mutual life otherwise.

The way it was scored in game is that black marked white as dead, then white marked black as dead which made the system count it incorrectly.

Were you aware that it was seki and trying to score appropriately and he changed it or were you trying to mark the white stones as dead?

[chef]

That actually makes sense. I did think that the white stones were dead.

[EdLee]

Hi chef, you also missed R1 and R11, and T10.
Good habit to fill in all the neutral points --
you learn (painfully) if some group lives or dies during this process.
W had to play R11 and T10 eventually. Both of you missed it, too.

R11, T10, and 242 -- 3 points difference.

226 is bad habit: you reduced your own liberties,
otherwise you had a chance to kill W that corner,
instead of seki.

Many things to learn from this game.

[schawipp]

I would count as follows

• black's left side = 80 pts
• black's center = 8 pts
• White: 12 at top, 9 in center, 18 at lower right corner, 4 at lower left corner and 4 at lower border = 47 pts
• The top right corner is a seki
• With the captures and 0.5 Komi, white has 52.5 points and black has 90

If you consider the seki as white territory, it would add 19 captured black stones plus four territory points = 42 points, then the result is w+4.5. Thus - you were indeed cheated.

But... - since you played significantly better than 9k in this game - your rank will be most-likely accordingly corrected during your next games, while your rank-obsessed opponent will most probably stagnate in his further development (as a result of his self-deception). So you can chose which is more important - KGS rank or improvement of your real^TM Go knowledge.

[Bill Spight]

Good habit to fill in all the neutral points --
you learn (painfully) if some group lives or dies during this process.

Amen, brother, amen!

Edit: Hmmmm. However, in the top right corner, if Black believes that the White stones are dead, he will not fill the dame there, and vice versa.

[Mike Novack]

Cheat is the wrong word.

You simply didn't see the danger that the upper right corner could result in seki once the outside liberties were gone. You lost the game by making small endgame plays worth far more than killing those stones.

Of course passively capturing could cost points too by allowing the opponent too many endgame plays elsewhere. But what would have happened had you made the capture at T13 while you had the chance? (say at 228)If you can increase liberties by using active threats you might end up with enough liberties in that corner* and could then go back to endgame moves elsewhere.

* if you have enough liberties to win that fight you don't actually need to capture the stones, they are dead. Just watch out that you don't need to respond as outside dame are filled. You never fill those yourself! It didn't matter since you already had too few liberties, but why did you play O15? Assuming you had enough liberties to kill in the corner, that's one of the dame you would watch in case your opponent filled it (reduced your liberties)and you would play to ensure
killing.

[Bill Spight]

You simply didn't see the danger that the upper right corner could result in seki once the outside liberties were gone. You lost the game by making small endgame plays worth far more than killing those stones.

Actually, he did not lose the game. It was mis-scored.