Large group death just basically mean a large group of stones, it could either be an invasion group, an attack and run group that grows, or even the used-to-be-territory-but-now-not group
Sometimes a group of stones is in a position such that no matter how their owner plays there is no way they can be saved (assuming correct play from the opponent). The stones are called "dead". Instead of capturing those stones, it's better to play elsewhere and retain the initiative ("sente"). You retain control of the game and your opponent is forced to react. You're not losing anything, because you can come back and capture the stones any time. If your opponent tries to save them you know a move that will prevent it.
Recognizing stones that can't possibly escape being captured, and knowing how to stop them escaping, is the study of "life and death". The better you get at this the less likely you are to waste moves or give away the initiative.
There's a common advice to lose your first 50 games as quickly as possible (http://senseis.xmp.net/?LoseYourFirst50GamesAsQuicklyAsPossi...). This will give you some basic intuition about the game. After a couple more hundred games, go becomes very beautiful.
The beauty of the game is appealing however so I want to get better at it. I'll working on losing more then :)
(1) Identify all the groups.
Most important are any groups larger than about 4-6 stones or groups that cannot be sacrificed for some other reason. You'll often see some straggler group which exists purely to disconnect your opponents groups keeping them weak. That one is small but important!
(2) Determine their status.
Essentially, their opponent decided it was time to kill this group and tried with all their might would the group be able to survive? You can be fuzzy about this ("there are a lot of possibilities for this group to live") or even economical ("it would take a lot of turns for B to kill W's group here, is it worth it?").
(3) Decide who "owns" every empty intersection.
Once you've identified the strong, living groups you'll see that they probably capture territory because they surround some empty intersections. These spaces can be invaded or reduced if they are too large (so that the opponent could possible attack inside and make a living group) or if they have open spaces (where an opponent could threaten to stream inside). There will also be a lot of points in the early and middle game for which nobody really owns and you can evaluate if one player merely holds greater or lesser sway over those intersections.
(4) Subtract maybe 20 points for each weak group that can't be sacrificed.
Saving groups that must be saved is an expensive operation and your opponent will probably cash in on you doing so.
(5) If it's early or mid-game consider each player's global influence.
For instance, a common trade is that one player will make a living group in the corner and take points while the other player will surround that group on the "outside" producing a large wall facing the center. This wall cannot claim to make territory since it doesn't completely control any location, but it certainly makes battles nearby tilt in the favor of the wall owner. This will translate to cash elsewhere for that player.
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Don't try too hard at any step. Part of skilled judgement is being able to do each step accurately (and include more important factors) much in the same way that materiel balance in Chess can be hard to judge unless you know how to contextualize it.
Also note that a well-matched professional game will be decided by just 1 or 2 points. Until your judgement is very tight or the game is very near the end it can be hard to be precise enough to see that.
Does this help your self diagnosis? If the computer ignored a capture it's because it didn't actually lead to a lot of territory gained, whereas whatever move it played probably did.
Somewhere I read about go it makes no sense to put stones on the area your opponent control because they will be captured. however
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In Japanese rules you lose points for playing in your own territory. The black stone in your example is dead, and a reasonable player would allow it to be removed, but there's nothing stopping them from claiming it to be alive and forcing white to play to capture it. At this point the only option is for white to dispute its life status, and to duplicate the game board and make a hypothetical sequence of plays to prove it to be dead without actually playing the moves. There's a lot of added complexity for no real benefit, because the end result is usually identical.
The next AI challenge is to have the AI make an argument that will convince everyone to adopt the One True Most Elegant Ruleset for Go. (http://warp.povusers.org/go/RulesElegance/ is an interesting page, along with his proposal: http://warp.povusers.org/go/MyRulesProposal/)
The AGA system of pass stones, bringing area and territory scoring into alignment, is very nice, but I think it's still a bit abstract for someone who's just starting out.
If a human tries to argue that b is alive, then either (a) that human is a novice, you can teach them, or (b) that human is a poor sport, and you shouldn't play with them.
Japanese counting is like Chinese counting, but assumes your opponent is not a jerk without explicitly handling cases when that's not true.
So, in this case, the black stone is auto-captured, and you get the territory within as well.
So, yes, playing white stones to capture is actually detrimental to yourself. But also imagine if black keeps playing. They would be giving away free captures since black can never create eyes. And once the space is almost filled white can play 1 stone to capture all of the black stones.
Edit: Another way to imagine it is if neither player could pass. While yes White would lose territory as it played stones, it would be compensated by Black playing stones that will be captured in the end. Thus it becomes a wash, and thus why dead groups are auto-captured.
I think scoring and score estimating is one of the hardest things to understand (for full games I still often use a $5 android app where I just upload a picture of the board game, help it convert to an SGF, and then it auto-scores it, though sometimes it's faster to just count by hand), especially since there's multiple ways of doing it. With simple territory scoring when the game ends the dead stones that haven't actually been captured yet still get removed and added to the prisoners pile and the prisoners fill in your other territory so it might feel extra painful to lose stones... With area/stone scoring you still remove the dead stones but prisoners don't (directly) matter for the score, since you're just counting stones on the board plus uncontested area. But if a game was X moves with black having X/2 stones but white only having (X/2 - 10) stones on the board, clearly (assuming X is even and no passes, or if passes then giving up pass stones) 10 white stones were captured at some point, so there's already that relative difference in score before counting anything else. With some qualifications, the results (and the relative scores themselves) from each counting system will be the same. Thinking more about your relative score instead of giving each player actual numbers might help; I feel slightly better if I lost by 10 than if I had a negative score, say -5 to 5...
When you've played a few proper games, I recommend joining a teaching ladder. Your games will be reviewed by stronger players. In exchange, you are expected to review the games of weaker players. Teaching can be just as valuable as learning, as it forces you to clarify concepts in your mind in order to explain them. Even if you're a high-kyu player, you can teach a beginner the basics.
https://gtl.xmp.net/ http://senseis.xmp.net/?KGSTeachingLadder
The person at the top of the ladder is essentially performing a public service, because they don't get the benefit of learning from a more experienced player. If they leave then the ladder doesn't collapse, the second strongest player simply becomes the leader.
Ladders are commonly used as a competition format in many sports. They provide an excellent way of giving players a challenging but enjoyable game. Teaching ladders are simply an elaboration on this format.
I think the biggest insight I had about Go when I was learning to play it is that the game commences on the entire board at once. At the beginning I was over-concentrating on a single "active" region. In reality, abandoning some "battle" and adding stones to an "unrelated" region is a perfectly sensible strategy as long as you think it will give you territory in the long run.
A good rule of thumb = don't needlessly increase the margin of your victory for any particular part of the board
I know playing against humans is better, but a computer opponent has the patience to watch me try hundreds of moves that they know are dumb, or let me cheat to test "what if" scenarios.
A variation explorer with a "What would GNU Go do?" button feels like it would be good for this.
One thing that has helped me is Tsumego problems, which cover local life-and-death situations. They usually include responses by the opponent to help you see why a move is bad.
I can sit down and maybe solve a tsumego problem, OK. Sometimes I guess a bit (MCTS!) instead of working out the whole tree, developing that intuition.
But tsumego are labelled with difficulty and that they are winnable.
But when I play a game, how do I know how if a certain local position is winnable, and worth spending the minute(s) to find how to win it?
For the former, you need to read out ALL variations, and not just one branch. For the latter, and your question, it's just simply a matter of solving lots and lots of tsumegos. In real game, people missed life and deaths situation all the time :-).
When I used the ladder, 15 years ago, their problem was that they had too many reviewers and too few students, so it was nice as a student :) You should give it a try.
What I really want is a kibitzing clock when playing other people: http://www.emptytriangle.com/archive/show/8