Moves 1 to 10  

is a 4-4 low approach. It limits the development of the corner stone and undermines some of its stability. is a basic development of two stones: the one space jump. It seeks development to that side, while providing a high degree of connectivity.

T ogether with -, the move at forms the micro Chinese formation.

is an attachment as well as a diagonal development. White removes a liberty of and makes it harder for Black to jump into the corner. is a basic defensive move against such attachment. A hane would not be appropriate here, because White's group is strong. is a splitting attack.

KataGo gives White a small lead to start with, which increases at due to early side development in its eyes, preferring an approach to the upper left. For it suggests an enclosure there or a 3-3 invasion of the upper right. Likewise and would be slightly preferred in the upper left.

Moves 11 to 20  

abandons the stones at the bottom side to create a new pole of development at the left. checks that stone, expanding his potential territory in the corner while limiting the development of . Such a tsume is the most common way to attack a stone. is a similar move, but due to the presence of it has no room for a base. Therefore we can see this move as a reduction. The stone may be sacrificed if the scale of Black's potential remains modest. is another basic development with the one space jump. It splits two enemy stones and prepares at either of them, at a or b. ^[1] and ^[2]

is a combination of a keima and an angle play, attacking Black's isolated stones. KataGo thinks it's a first mistake, shifting the lead to Black. KataGo suggests a large knight in the lower right or a rather unusual wedge of Black's one space jump.

is another safe development. One would expect b here, which is more aggressive towards .

checks and combines a diagonal play with the keima of . The aim is to expand the scope of the attack on the two lone black stones. Locally, would be played at c, but then d completes the encirclement. Therefore, is an attachment, the basic move for creating something viable in a hostile sphere of influence. deserves a diagram of its own.

Why not hane  

A hane at the outside is the common response to an attachment but then separates two white stones in a manner that is considered painful. White is helping black.

Why not cut  

White can cut the black stones. Now black has two chains of solidly connected stones, while white's stones are connected in a crooked way. Although it is not easy to see, there are too many weak points in White's position this way: a and b, leading to c. It would not be possible to keep the attack going on all black stones, which is necessary for White to keep balance with the black sphere of influence on the right.

Capped in  

[1] unkx80: Players at a certain level should have the intuition that is the only move. See diagram below.

unkx80: If plays the "more usual" knight's move, then caps the stone in. At the same time, more or less connects with , forming some kind of influence and exerting more pressure on the two Black stones at the lower left corner. This position is disadvantageous for Black. Therefore, must separate the and by jumping out at . The difference is quite stark.

unkx80 (2014 February 17): It seems that the commentary by An Younggil is updated to include this variation, but with the comment "This capping play is also conceivable and it's another game." Oh well, what do I know!

Dieter: KataGo also thinks it is playable.

No miai  

[2] One could ask why Black doesn't play here to attack or at a to attack . kb: I think the one-point jump is strictly better than the knight's move. The reasoning here is clear: when attacking two sides of equal strength, play honte as an indirect attack, making miai for the other player of defending both sides. One of honte's tenets is making oneself strong first, then fighting. This idea should be contrasted with a leaning attack, another type of indirect attack that should be used when one side is already stronger than another.

I am not sure if this idea exists on SL anywhere yet, but I have had pros teach me this technique as well as using it myself to great success in many games. I think this concept comes in at the low dan range. Once you see it in action, you will understand when to use the knight's move and the one-point jump for attack. It is certainly an element of haengma but I would appreciate a librarian's input if they know the word for this type of play.

Moves 21 to 30  

Black fixes his connection through and , then moves out with a diagonal play. Let's discuss , , and

Why not Hane at the head of two  

The usual answer to a move like would be , a hane at the head of two. Dieter offers as an answer: Black gets out quite comfortably. So White kept the attack going with a instead. KataGo prefers the connection at b

Why not Hane at the head of two (An Younggil's answer)  

An Younggil gives this variation. However, it's not yet clear to me (Dieter) what happens if White resists with at , or at a. KataGo agrees: is a small overplay giving White a capture. Simply connecting is better.

Atari from the other side  

If ataris inside to cut through, at here, Black will gladly capture two stones and get a good position at the left side. White can not allow such an even exchange in his sphere of influence.

Why not simple hane  

When White plays move 28 at here, the common answer would be then to form a hanging connection. Black chose to apply the one two three principle and play immediately. The omission of the - exchange will leave more potential for him to still enter the corner.

White's better alternatives for  

An Younggil thinks would have been the better choice and suggests as an answer against Black's cut at . Rob Van Zeijst thinks was in the right direction but not flexible enough and he proposes a instead. It is instructive to read both commentaries. KataGo proposes b

KataGo's evaluation  

KataGo evaluates as a mistake (2 pts). This aji including sequence is one possible result

Moves 31 to 40  

The sacrifice tactics of to require more advanced understanding and cannot be discussed from a perspective of basic technique. There is a fork at : if it is played on the other side, at , then Black will eventually get a move at a in sente. To understand this, we refer to the analysis by Rob Van Zeijst.

It may be unclear why White follows suit with instead of capturing the black stones on a large scale at a. We refer to An Younggil's lengthy analysis there, with some hair raising variations. When analyzing with KataGo, a is indeed the "blue move", so we need to investigate An's analysis again.

Moves 41 to 42  

This diagram completes Black's maneuvers to create aji at the lower left. looks like a strange answer to the atari of . The usual move would be to capture at a. In the game, a move at b is sente for Black. As An Younggil points out, if White had played a instead of , then a move at c would also be sente for Black, because it threatens to turn the corner into a ko. reduces Black's options for later connections underneath but already having b available in the future is a bonus for Black.

Moves 41 to 50  

The one space jump of is a basic move for defence. makes a defensive horse head shape while it's also keeping the black group in check. , a large knight's move, is a sort of counter attack, but it has a higher degree of flexibility than a simple keima.

- is a typical attachment-hane exchange, where White tries to establish a position in Black's sphere of influence. gives some leverage for White at a next, but if Black would retreat to b instead of , then it's too easy for White.

is a special move, trying to cut the large knight's move. Black's reply is not intuitive:

Normal hane  

The normal answer would be , to try and preserve the connection within the large knight's move. creates a complicated situation with a cross cut. White can next aim at separating one of Black's one space jumps, with a or b. An Younggil gives many variations from here. The summary of those is that either White got an easy settlement at the bottom, or the fight becomes very complex in the centre or White acquires sufficient strength to attack Black's dragon left of centre. Apparently Lee backed off here and decided to keep things under control at the bottom and suffer a small loss in the centre.

Moves 51 to 60  

is a leaning move: if Black plays the usual hane at a, White cuts through the small gap at b. White is looking at a chance to wedge at c. Black doesn't answer locally and instead weakens the White group with . This is an application of Make Weak Walk Along With Weak.

is the slowest possible haengma: the solid stretch prevents a potential wedge.

was criticized for bad timing. The local purpose is clear: a counter hane applies leverage to create a small position in Black's sphere of influence.

Yielding  

This is one of the variations shown by An Younggil: if gives in to the attachment, then up tp two cuts remain at a and b.

Answering in the corner  

If answers in the corner, then the scope of the bottom becomes smaller and is not as severe as in the game.

KataGo's variation for 53  

This is how Katago wants to play. is at a and b is kept in reserve, should a central fight develop.

Moves 61 to 70  

Black ignores White's local pressure for a second time and plays . makes a false eye at the circled point, according to An Younggil.

Moves 71 to 80  

makes things easy for Black in the centre: he falsens an eye and he could next connect to the bottom stones or cut White at a. White breaks through at the bottom and Black eats the two stones in the corner. This may look like an equal exchange or even a bit slack by Black but we will later see that the marked stone has the potential to link up to any of Black's groups, because b is sente!

fixes the looming cut. would ordinarily played at c as a faster paced defense.

Moves 81 to 90  

and start building a wall with outward influence.

Moves 91 to 100  

The wall continues being built. White is running ahead? but his wall is facing an area which has already been played out.

is an angle play on the vital point of White's group. is a capping play a very natural move for attacking a group. As An Younggil points out, is an efficient way of preventing a Black move at a. White would answer b and in the resulting sequence, Black's 3 stones remain dead.

Moves 101 to 110  

and are two more capping plays, natural moves that check White's development and even put pressure on his stability. The fact that Black can play these natural moves is a sign that things are going well for him.

is a move grudgingly played: White is walking on neutral points to seek asylum. With Black starts converting his attack into potential territory.

is a tesuji to cover his cutting points at a and b as An Younggil explains.

Moves 111 to 120  

Up to , White has effectively fixed the cut and Black has become stronger. Then is a leaning attack. defends the group and capitalizes on his attack by fencing off a corner that was originally one where White played first.

At , complications in the upper right start. We can say that the game has become difficult for White now, so that he needs to seek complexity.

Moves 121 to 130  

Black does not fear the challenge and cuts at . White surrounds at . With and , Black's originally strong wall starts showing signs of weakness. Black has two groups to take care of now. White has relieved one of his groups with the - exchange and only needs to take care of one group.

Moves 131 to 140  

is a move comparable to W110 earlier. is a natural move for attack but according to the AGJ pro commentators called it a mistake.

Moves 141 to 150  

With and Black provides life potential for his top group. White does the same with and but at the expense of Black's corner becoming strong territory. shows the purpose of . He sacrifices the corner for life at the top.

Moves 151 to 160  

makes life for White's group in the corner. According to the professionals, was a timesuji. Everything is about to stabilize now.

Moves 161 to 170  

With , Black finally answers White's leaning move , in a natural way, cutting off all support for the top White group. Next, ...

Moves 171 to 174  

White lives upt to : a and b are miai for life.

Moves 175 to 180  

The first big endgame is at the top right, because it affects both groups in their life and death status?. According to Rob Van Zeijst, capturing at is larger than playing a, because that would lead to life in seki. According to An Younggil there would even be a ko (further unexplained).

Moves 181 to 190  

is the next big sente endgame and finally draws out a stone that seems to be lost, thanks to the aji on the lower side. To make matters worse, as An Younggil explains, the White group is threatened to be left with a famer's hat? nakade, which is a dead shape. fixed that issue, but this means the move was again sente.

Death in a big corner  

This sequence would kill.

Moves 191 to 200  

At B191 Black finally takes gote, removing aji here. A cut at a would damage the black territory or still cut off the big black group and link up to . Victory is assured. According to all commentators, the advantage is about 15 points now.

Moves 201 to 210  

is White's last sente for now and forces White to take the smaller eye of the two available second eyes for his group. Then is an awkward looking move, explained by the professionals as inevitable from the nature of Lee Sedol: it potentially squeezes out an extra point due to endgameaji, which is obviously not necessary at this stage of the (won) game.

Moves 211 to 220  

The virtual sente of which has haunted White for almost the entire game, is finally played at B211. The remainder of the moves are obvious reductions of Black's left side.

Moves 221 to 230  

Here we see another interesting endgame pattern at work. Black cannot capture the white stones. He throws in another sente at , ...

Moves 231 to 240  

... forces the capture and connection at , then connects the ko at , now that overall temperature is dropping and lives at . If at , then at and the capture of white stones is bigger.

Moves 241 to 250  

As An Younggil points out, is as good as a resign call:

Move 251 - White resigns  

turns the corner into seki or ko. It is appropriately ironic that Gu Li resigns by setting up a loss of the corner that has been the root of all Black's advantegous maneuvers throughout the game.

Move 251 - futile resistance  

To clarify the problem here, if makes life for his group below, then will kill the one above. White cannot play a and if Black can play there, then a snap back at b is imminent. If White covers b, then still it becomes a seki. The same will happen if at c.

If is played at a, to start filling liberties, then is at , which reduces White to one eye there and again leads to seki, unless White answers at c immediately, which leads to ko.

In any of the variants, which are well explained at gogameguru, the loss is huge.