:

Black is shut in now, so must cut, and thereafter save the cutting stone.

(Referenced by 219)

: (A 519)

White should not capture Black's group with . The hanezeki will be dissolved, but White will be unable to capture one of Black's group on the left side, to get compensation for her loss on the right side.

: (A 521)

White must live on the lower side. White will not win the semeai starting with .

Nor would White win the game, if she could win that semeai by only one move ( 527), because the shape on the left side is not fixed yet, and Black would then - with a move at - ensure that White's group can only get one eye, so killing White's entire left side.

(B 528)

White could precede her move at by playing at first, threatening Black's top left corner. She will destroy several points of Black's territory, but not gain enough to turn the tables.

: (A 530)

Black still cannot take three white stones with . As already shown with the variation for ( 113), Black's group has one liberty too few to win the resulting semeai.

(B 531 / C 532)

Black cannot capture White's group on the left any faster with another move - for example with , or .

: (A 544)

Black must not capture White's three stones with . White will get two eyes on the left side, and win.

: (B 545)

White cannot break through on the third line at . She will be forced to capture the hanezeki's tail, as usual resulting in the loss of the game.

: (C 546; D 546)

Black cannot play at , or . White's group on the left side will live in seki. Thus White does not need to capture the hanezeki's tail, and she will win the game.

 : (91 548)

White cannot play at 91. Black will capture her group on the left side, eventually.

: ( A 1093a)

Just before the final move of the Nakade Sequence, KataGo (one of the "new" Artificial Intelligence based Go playing programs of superhuman strength) suggested White giving the surprising atari at Black's single stone below with a move at A, instead of giving atari at Black's group at the edge.

Black will be unable to resist and has to surrender passively, eventually losing four points of territory in the Capture Variation that will now end with a Black win by only one point.

Details can be found in Volume II of our book.

We ask for your kind understanding that we have not been able to adjust the structure of our website according to the new correct order of moves, but only added a corresponding note in the affected variations.

:

Black has created a nakade - oversized, but with cutting points.

Please note that this is the first "real" gote move in the solution's sequence so far. There is no need for White to capture immediately at , which is the classical line of play ( 717).

The large fight on the board, between Black's eyeless group in the top right, and White's group on the left side, which cannot get more than one eye, is already decided. So it seems technically correct to continue with the endgame on the left side of the board, and to finish the Main Semeai later. This is based on a suggestion of Professor Jeong SooHyun 9p ( 810).

: (B 549; C 550)

This tsuke was found by Yamada Shinji 6p. It is possible now, because White's group on the left can come to life, by capturing the tail of the hanezeki with at any time. Compared to the classical Fujisawa solution ( 754), with its move at , it gives White a gain of one point, locally.

There are slight differences in the evaluation of a few moves - compared to our solution - when the endgame on the left side is played last, and White continues with capturing Black's nakade with a move at .

: (B 560; C 563)

Black should play the exchanges of , , and especially , no later than now, immediately after Yamada's tsuke in the top left. If he does without the latter exchange, White will start the semeai in the upper right with a move at 95, instead of (=), and gain two points. To do without the atari of costs Black one point.

: (D 566a)

White will not answer the atari in the Hanezeki.

Harry Fearnley found that playing the forcing moves Black and in the Hanezeki just after Yamada's Tsuke in the upper left corner (; chosen by us for no specific reason) is the wrong timing.

Black must play this exchange earlier in the game!

We ask for your kind understanding that we have not been able to adjust the structure of our website according to the new correct order of moves, but only added a corresponding note in the affected variations.

 : ( 100 566k)

During the move sequence that follows the tsuke of Yamada Shinji in the upper left corner, KataGo (one of the "new" Artificial Intelligence based Go playing programs of superhuman strength) suggested White playing the crosscut at 100 immediately.

As with the tsuke itself, Black has no real resistance at his disposal and has to surrender passively, losing another three points of territory in the top left corner. The Semeai Variation will now become a drawn game (jigo) (with the other of KataGo's new findings remaining unplayed).

We ask for your kind understanding that we have not been able to adjust the structure of our website according to the new correct order of moves, but only added a corresponding note in the affected variations.

: (A 567)

This move prevents one point of territory for Black below, and is sente. White can change the order of moves, and also play at after - , or after .

: (110 569)

Black gains no advantage by playing at 110, instead.

: (114 573)

Black should not connect at 114 now. White will give atari in the top left corner, at , and gain a resulting advantage of one point.

:

White captures nine stones, but cannot get two eyes.

: (120 574; 119 575)

This is an important tesuji for attacking White's eye-shape. There is no other way to prevent two eyes.

:

White could play at 120, instead. With , , , it results a change in the order of moves.

:

This is the second gote move in the solution's sequence.

: (D 576)

The classical line of play continues with an atari at , instead, which Black connects at ( 718). However, it seems to us that it would be technically better to play this move at , just now (Black will have no use for his "local" sente), or even later (as we have chosen in our solution).

demonstrably works completely independent of the rest of the board ( 822), while - in principle - the success of the atari at depends on ko (assuming that the liberty count is not an issue, but what is not the case here). This is especially true with the professional solution, where the guzumi exchange ( / ) has not been played beforehand.

Despite the fact that Black cannot successfully fight, and win, this ko (please refer to the appropriate variation of the professional solution; 731), we decided to have the unconditional alternative in our solution's sequence.

White does not profit from further reducing Black's potential territory on the left side, starting with a move at , instead.

:

Black might consider to insert the kikashi of Michael Redmond 9p in the bamboo joint, at 134, just now. However, if he wanted to gain an additional liberty for his large group, he would have to accept losing points (when White captures at 127, later). Otherwise, this will result in a change of the order of moves only.

Therefore, it is not necessary for White to play her own kikashi at 124 earlier, to steal Black's kikashi its impact.

:

With the endgame on the left side already played, White could also give atari at 126 with this move. Otherwise, the order of moves will matter here (please refer to 552).

(Referenced by 823; 823)

: (146 578)

This is the latest moment that White should occupy this point inside her eye, but for general technical reasons only. With the special situation in the problem, she might also wait one move longer.

:

Filling in the nakade shape like this is technically correct, according to Ōhashi Hirofumi 6p ( 820). The classical sequences continued with a move at 160 ( 719). We adjusted only our own variations, but not those of the professional solutions.

: (A 580)

With , Black takes a point in the lower right corner, which he otherwise would have played later during the semeai. It is a bit counter-intuitive to recognize that this move does not work now.

(Referenced by 74)

: (A 582)

Black cannot capture White's three stones with .

Black is obliged to take a liberty inside White's eye - any other move leads to the Punishment Semeai, and is a disaster for Black! This move is being played because it takes a liberty, and not because it is an eye-stealing point as coincidently also is in the classical nakade-filling sequence.

(Referenced by 26; 192)

: (163 583)

For the second time, a moment has come when White has to make a decision that will affect the rest of the game. Does she rescue her group on the left edge, or is it better to capture Black's big group in the upper right?

However, fate has not been kind to her. Her groups on the left edge and in the hanezeki at bottom right are now one stone too large; on the other hand, Black's tail of the hanezeki has one stone too few. Whatever White decides, victory will be denied her.

White chooses the main variation, which we call the "Semeai Variation". It is worse for her to capture with 163 in the centre (= "Capture Variation"), instead.

: (A 586)

Before Black can attack effectively in the hanezeki in the lower right, he must reduce White's group on the left side to only one liberty.

:

Black had to wait until now to be able to continue in the lower right corner.

: (A 587)

White is two moves ahead, and takes Black's big group in the top right off the board. Black's top right group needed three additional liberties to enable Black to win this semeai.

:

We now can see that the additional seki of the -/-groups (compared to the classic version of a hanezeki, where the -group is not present), has the effect of splitting the white corner group into two, so that Black captures only one part. This serves to adjust the score.

(Referenced by 29; 923)

Black wins by three points.

This result is fairly stable with respect to small changes of moves, as well as to the order of moves, and is the standard result for the Semeai Variation with the double throw-in.

Igo Hatsuyōron is a Japanese classic, so it is natural to use Japanese territory scoring throughout this book.

Please also note that the Igo Hatsuyōron was written in an era, in which Komi was not yet used.