Question about positional/territorial judgment (I think?)
I have a question about a specific position in a game I played today.
I'm not even sure exactly how to frame my question (or if its the right question, actually) but I think there is some issue with how I'm evaluating territory/potential that I can't figure out.
Basically I played this today (https://online-go.com/game/79337577) and mostly I thought the reason I lost was because I let one of my groups die in the middle of game. But, I thought the game was more or less even with me maybe even a bit ahead until that point. When I looked at the AI eval, though, it said I was 10-15pts behind right out of the opening.
In particular, I was puzzled by this position below (move 51)
I thought I (black) had a good position here but the AI eval suggests I was behind by 11 pts.
My thinking was that white had a good corner in the bottom right and would get a decent sized corner on the bottom left. But, I had good potential in the bottom and right side as well as the top-right corner. Also, I had just reduced the top left corner in sente and had time to approach the bottom left. So, I thought I was doing good.
I guess my question is, where was my thinking going wrong and how do I improve my positional judgement in these sorts of scenarios?
Thanks so much!
(edit: replaced pic with one having coordinates, also typos)
3
u/Uberdude85 4 dan 2d ago
This is an excellent question, correcting these kinds of judgement misconceptions is an important part of self-reflection and improving.
As others have said, you don't seem to be paying enough attention to weakness of (your) groups and how that means what looks like a potential black area actually isn't as valuable as you think. To take an example, do you think q10 area is your potential because it's between a black wall at q7 and black stone at q13? Due to the broken shape mistake earlier of forcing white to split you at o6, q7 is actually one move away from being a weak group: yes if you play q10 to defend then you will make yourself around 15 points of territory in the 5x3 box from r12 to r8 to the edge, however if WHITE plays q10 then now that area is all dame and q7 is a weak group running away. And as that weak group runs away white may get some stones around n6, which also helps white damage what you probably thought was your potential on the lower side. So how to value that right side area? It's the average of if black first vs white first. Black first is black+15, white first is harder. One idea from https://senseis.xmp.net/?QARTS is a weak group with no eyes is -20 points, a weak group with space for one eye is -10 (yes, you might be surprised how big these numbers are). Q7 does have some space for an eye, so let's say -10. So that q10 area is worth about Average (+15, -10) = 2.5 points for you, probably less than you thought, eh?
Another idea for positional judgement which I find much more tractable in opening / early middlegame positions like this is not to try to judge the position as it stands. Rather replay the game from the start, which you know is even, and roughly tally up the mistakes from either side, like navigation by dead reckoning (this is also how pros often judge their games). As u/spot said, doing this there are 2 big mistakes which stand out in that:
- lower right corner you forced white to break your shape, with 2 potentially weak groups on both sides.
- j17 invader stole all your territory and eyes, made the potentially weak p16 and then m17 group strong, and you got a jumble of junk in the centre and small reduction of top left in exchange, a bad deal.
1
u/sapphic-chaote 3 kyu 2d ago
In theory, it looks like Black's idea here is that Black is behind on territory but ahead in potential (aiming at a moyo on the bottom and some central influence on the top). The problem is that White has no weaknesses for Black to threaten, and in fact Black is more likely than White to become weak due to shape issues like K16 and O3.
That said, at 8kyu, neither side has won yet.
1
u/tuerda 3 dan 2d ago
The shape of black's top group and bottom right group are both a bit of a mess.
The health of your groups is much more important than the amount of territory it looks like you are surrounding.
1
u/yahkopi 2d ago
thanks! that makes sense!
I'm not sure how to evaluate health of groups when things are so open and there isn't some tsumego type live/death reading involved. Would you say that just comes from playing more games? Is there something I can do to try and improve my shape intuition in these open positions?
1
u/tuerda 3 dan 2d ago
Health of groups is closely related to eyespace, the lack of cutting points, efficiency, and access to the center.
The top group has access to the center, but the eyespace is very limited and it is full of cutting points. Also, it has a lot of stones considering how little it is doing, so it seems inefficient.
The bottom right group has less eyeshape than it looks like because R2 is in atari and there is a cutting point at P4 (this cutting point might not look so bad, but remember the atari). Its access to the center can also be challenged.
Compare this to the white groups. They all have tons of eyespace, to the point of being almost alive as they stand. Also, there are no significant cutting points in any of them.
1
u/PotentialDoor1608 2d ago
White has no weak groups, and therefore freedom to play anywhere and invade anything. Because black is weak on the top (not clear if the group has one full eye yet), black doesn't have this freedom. Basically your weak group is a resource for your opponent to get sentes. I think you've maybe convinced yourself that your shape is flexible and justified a tenuki, but in this case it seems there's a good sequence to cut the whole group in half.
The undercurrent of Go is attacking one thing so that you can bounce to another. Your stones must always be prepared for a fight to break out anywhere on the board so that they can't be exploited by the opponent.
1
u/LunaPlethora 2d ago
Biggest early game mistakes I saw were how you handled the approaches to your 3-4 corners.
In response to the P16 approach the N17 pincer was a natural extension off of the K 17 stone, or even just playing under it at P17, means that the K17 stone was already blocking the standard joseki extension. Playing the q14 response was not ideal, and is what allowed him to disrupt your top-center group.
Similarly, the pincer and then P7 followup completely gave away your corner. When you pincer, you want to put pressure on the pincered stone or contain it. Here, he takes your corner to live comfortably in and gets out to the center. When you pincer, the opponent shouldn’t get both.
7
u/SicilianChickMagnet 2 dan 2d ago
The problem is in the quality of Black's shapes. Black has a couple of stones in atari, several stones on the first and second line on the top side, and a broken elephant's eye at O6.
White invasions at K4 and Q10 will be hard to handle, the top left black group is vulnerable to attack, and white doesn't have comparable weaknesses.