In the attachments you will see that I invaded at g18. I'm Black. White had the whole top of the board and I was getting nervous that they were taking up too much territory in the top, so I decided to invade though it looked like a rather risky invasion. The invasion ultimately worked in the sense that my unit was not captured. I did ultimately win the game by 6 points. If you want to see the whole sgf file you can. The invasion is at move 47. The first attachment shows the invasion after about 15 moves after the invasion, the second attachment shows the invasion when it was done. I was 16k and my opponent was 14k.

"Was my invasion correct?"
No.

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Amsterdam, soon.

Since you have the sgf, why not use the (excellent) sgf-tags the forum provides. Like this:

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I guess I underestimated the power of the sgf tages. Like I said my invasion is at move 47.

See lovelove's reply, Post #2.

If white on move 70 plays D19 (not E19 or F19 as in the game), I can not see how your invasion survives.

And continuing from the last post (3 is actually redundant as "a" and "b" are miai):

Click Here To Show Diagram Code

[go]$$W70
$$ ----------------
$$ |.4312b.aX......
$$ |5.XOX.XXOXXOO..
$$ |.X.OXX..OO.X.O.
$$ |.XOOOO...O.O...
$$ |.XXXXO.........
$$ |.O..........O.X
$$ |..O.O..........
$$ |......O........[/go]

Now you get to die on both sides

I think your invasion is wrong because your corner group is weak so making white any stronger might end up killing you.

Also look at the white group it seems to be very strongly connected. to each other or out towards the center so there is no way you could split white's stones into weak groups.

I'm interested, because this looks like the kind of pitfalls I run into.
kylefoley played that move because the top of the board looked so overwhelmingly white. Is the situation actually bad for him? Does he need to invade somehow at this point? Or can he get away with just reduction?
While white's potential territory on the top looks big, Black has some nice framework on the right and lower sides. It occurs to me that if he uses these stones to extend towards the center, quite a bit of the potential white territory on the top half might disappear.
Or is it too late and should he have done something about it earlier?

What you have there is territory envy

Many of us suffer from it. The cure is to learn to count.

I don't think you need to invade, to me it looks like black is ahead so far. So you should either make your territory more secure, or just reduce white (or better yet, find a way to do both at the same time).

Something like 'a' instead of looks really big to me (but I'm not all that strong, and this is the weakest part of my game)

Click Here To Show Diagram Code

[go]$$Bcm47
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X O . . 1 . . . . . . . . . . . . |
$$ | . X . O . . . . . . . . . O . . O . . |
$$ | . . . , . O . . . O . . . . . O . X . |
$$ | . . X . X O . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . O . X . X . . |
$$ | . . O . O . . . . . . . . . . . . . . |
$$ | . . . . . . O . . . . . . . . . . . . |
$$ | . . X . X . . . . . . . . . . . . . . |
$$ | . . . , . . . . . O . . . . . , X . . |
$$ | . . O . X . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . X . . . . . . . . . . a . . . |
$$ | . O O . . . . . . . . . . . . . . . . |
$$ | . X X X . . . . . X . . . . . , X . . |
$$ | . X O O X X X . . . . . X . . . . . . |
$$ | . O . . O O O X . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

You should display your rank. I'm not sure I should listen to you since I don't know what your rank is.

I remember some years ago a number of us, including some dan players, were trying to solve a problem on Sensei's Library. The key play was found by a beginner.

Listen.

_________________
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.

LOL

my official KGS rank is: [?]

Thank you for pointing that out.

No offense, but at 16k you should take all the advice you get seriously. Trust me, if anyone tried to offer you genuinely bad advice, he would get smacked down pretty quickly. Go players are a belligerent bunch!

If you don't understand someone's advice, you should ask for a clarification... and don't accept "because I'm 4d" for an answer.

Even pros can't clearly explain "why" about many things in go, because they just know it by experience. Like, having a good feel about certain moves, because it usually worked out well. "because I'm 4d" is enough for a 16 kyu. Studying go is all about memorization and reading practice. The other various parts of the game will be naturally understood by experience.

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Amsterdam, soon.

Lovelove, if you say "Do tsumego - because I'm 5d," I'll obey you. If you say "Memorize joseki - because I'm 5d," I'll obey you. If you say "Don't invade here - because I'm 5d", I'll have no idea what you mean. Don't invade here, why? Because no invasion can live? Because there's a better invasion point nearby? Because there's a bigger invasion on the opposite side of the board? Because reduction is bigger? Because I'm leading and need to simplify the game? Because he has too much power in the center already, and I can't give him more? How will I know whether to invade or not next time if I don't know what was wrong with my invasion this time?

('you' is not you)You will not know what is right until you get stronger from tsumegos and joseki memorization and lots of game experience. I just can say, that invasion is nonsense, because I have experience of killing that kind of invasions, my reading tells that will bring a horrible result, and I haven't seen an invasion like that in my memorized pro games or diagrams from various books. How could I explain this? Or is this already an explanation?

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Amsterdam, soon.

Well, if I asked whether an invasion is good or bad, I'd expect to see some possible sequences and where they lead, not just "because I'm 5d and I say so".

Let's imagine for a moment, that the invasion in OP's question was in fact good, but the opponent killed it anyway. Wouldn't it be nice to show where his continuation went wrong?

If my memory serves me correctly you did this to some extent in your first reply, although only showing one move.

edit: and for OP: practically everyone who writes here is currently stronger than you, and their advice is potentially useful to you (and the ones that are weaker than you most likely don't offer advice). Naturally advice from a 5d is more likely to be correct than advice from 5k, but still 5k can very well be in a position to give you valuable advice. Most people don't give advice unless they know what they are talking about, and if they do and err, the other members will soon correct them, as jts pointed out (I once gave advice that my teacher had given me, and I was soon "shown my place", and I have stopped giving advice altogether).

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If someone asks "How's this move?" I'll say good/bad/I don't know.
- "Why?" "Because it looks so."
- "Suggestions?" I can point out several considerable moves.
- "Sequence?" Very many many kinds, I'm not good at pointing out some main sequences, unless it is joseki.
If "Why?" again, "I don't know, do more tsumegos"

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Amsterdam, soon.