Hi, I played this game a few days ago. Probably should've invaded the left side at some point, but I just don't know how to invade after he plays D10. He made some pretty big mistakes early on the right and later in the bottom left that won me the game. Comments and advice greatly appreciated.

If you have some cash to plonk down on go books, Workshop lectures Vol 2 gives a good breakdown on how to approach the problem of invading.

Basically:

An invasion is "easy" if there are at least 21 "open" points (stones on the 4th line don't count, because you can slide under them. So count the open spaces between enemy 3rd line stones) and if a path to the center is still open (meaning not blocked by one or two space jumps).

To start the invasion, play on the 3rd line (easier to make life) near a weak group. For instance, if there's a lone stone at the center star point and a 3-4 enclosed corner, start at the star stone. Usually a knight's move from the weak group is correct (the weak stone is hopefully a 4th line stone). If he protects territory you can run to the center. If he caps you can live locally. If it's a 4th line start point stone in the corner, that's probably the weaker group so you should play a low approach against it.

If the situation looks tricky, you can play contact against a strong group first (say, the 3-4 enclosed corner in my previous example) to build up stones for support. He will probably respond to each forcing move, so you get them for free (they don't change the score). Make sure to "aim" your stones so they'll be useful to your future invasion (if your future invasion will be able to "see" the stones you're placing, you're doing fine). You burn aji doing this, though, so you should try to avoid doing this unless you think it's needed. Note that once you start the invasion proper it's too late to throw around forcing moves against a strong group.

If you have to live locally it's a tsumego and you'll need strong reading skills. Generally make as many forcing moves as possible that increase your eyespace, and then make one big final gote move that really increases your eye space, and hope that you have enough to live. You'll get better at this as you get stronger (or is it vice versa )

Second, timing is important. If you invade too early you give the opponent a weak group to chase. Against a skilled opponent you will lose the game right then as they build up points for free and you just try to escape and make life. If you wait too long he'll go back and protect the weakness and you won't be able to invade anymore (well, you can always try, but it becomes a very risky proposition!) So the optimal time is right before they would burn sente to finish off the moyo and it'd be too late to invade easily (right before the moyo is finished). So it's a bit of a game of chicken.

In your game, would probably be the time to invade white's moyo. C12 or C8 would be my moves. White will probably protect territory, and you'd run to the center. Alternatively you could wait a bit more. In which case needs to be an invasion at C8. Witt the you made ingame, you're telling white you're okay with his moyo. Which maybe you are, I don't know (depends on your game plan), but if you intend to invade that was your last chance for an easy invasion.

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1k KGS

Some of your shapes are good, others not so good. A few ideas:

Thanks a lot guys. This really helps me out.

39: He missed S14. It saves his group.

57: Too close to your own strength. Try L11.

59: A good idea, but it leaves a gap which he exploits. A slightly firmer play at K14 leave him no options but death.

61: Contact plays tend to strengthen weak stones. Something like K16 is better. Make him heavy, but keep yourself strong.

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