Haphazard Review: The Unfortunate Ko

Standard

1-291

In the game of Go, a mistake can appear out of nowhere. Just when one thinks the game is over, a misplaced stone can turn the win into a defeat or an easy win into an all-or-nothing ko fight.

1-5

Brown Stone played Black. Black was happy to play the Chinese opening. White played A. B is the standard approach to the Chinese opening.

variation-move-6

The Standard Chinese Opening

This looks like the standard sequence with a Chinese Opening.

6-7

To extend or not to extend

White played A. Black expected B.

variation-move-8

The Chinese Opening in Action

This is the standard continuation according to Kato Masao. Black can build on the North East.

8-35

Black’s approach at 11 used the power of Black’s thickness on the North West. White 18 looked aggressive. Black’s South West group looked settled. Black 19 used the power of Black’s North West thickness. After the exchange of Black 23 for White 24, Black was not worried anymore about the North West corner and West group. Black 25 should be at Q6 for better balance on the East. White 34 looked very slow. Black 35 ended the opening.

counting-1

A Close Game

Counting

Black (Triangle) Pairs

North West – 6

West – 2

East ~2 (since it is not yet secure)

S – 2

North East – 5

Total – 17

White (Square) Pairs

South East – 9

North – 3

Total – 12 +6.5 Komi

The game looked close. The South West looks very weak, so maybe Black should have played B2 before G4.

36-86

The jump of of Black 37 ensured Black would not get surrounded. Black 39 looked very passive, but Black thought the invasion at R8 would give Black a useless wall. The invasion of White 56 looked very bad. Black took pride in cutting White with the wedge at 71.

87-137

Black also took pride in finding the tesuji at 101. After Black 105, White was captured. Black 121 aimed at keeping the pressure on White’s center dragon. Black K8 might have been a better play.

138-170

Black continued the capture of White’s group on North from 138 to 157 at the expense of the North West.

counting-2

Big Capture=Big Lead

Counting

Black (Triangle) Pairs

North East – 42

West – 3

South – 2

Total – 47

White (Square) Pairs

South East – 13

North West – 2

Total – 15 +6.5 Komi

The big capture gave Black a big lead. The game ended here. Black should have thought of playing at B2.

171-220

Black 171 aimed at connecting the West and South group. Black should have surrendered the South West after White played 172. White would only gain 28 points in the South West. Not big enough to overcome Black’s lead. Maybe Black B15 would have been better because it also threatened the capture of White’s one-eyed dragon. Black 173 was okay, but Black 181 was a mistake (E8 would have connected Black and saved a few more points). After White 186, Black realized Black only fed White. The South West was about 26 points, not enough to catch Black’s lead, but Black should not have wasted time on the South West. Black continued feeding White with 187.

221-259

The Calm Before the Storm

260-261-the-unfortunate-ko

The Unfortunate Ko

Black 261 was Black’s biggest mistake. It led to an unnecessary ko fight and forced Black to capture the four marked White stones.

262-265-the-ko-begins

Ko Fight Begins

After Black 265, the unfortunate ko fight began.

counting-before-ko

The Ko Fight’s Value

This ko is worth 46 points. White captures 17 Black stones, saves the four White stones, and gains the two points marked x (total 44 points). Black also loses the two points marked o.

Counting

Black (Triangle) Pairs

North East – 39.5

South – 8.5

West – 2.5

Total – 49.5 = 99 points

White (Square) Pairs

South East- 14

South West – 9

North West – 3

Total – 26 + 6.5 Komi = 58.5 points

White wins by 5.5 points if White wins the ko. White needed only 41 points to win.

266

White 266 is worth 45 points, White captures 18 Black stones and gains the 3 marked points (39 points) while Black loses 6 points. Black needed to answer.

267-269

Black 269 is worth 37 points, Black captures 17 White stones (34 points) and White loses the marked points and Black 269 (3 points). Even if White takes the 46 points, White only gains 9 points. Black would still win. White needed to answer.

270-272

Not Big Enough

White 272 was worth 18 points, White captures four (8 points) stones and Black loses the 8 marked points and captured White stone (10 points in all), which was not enough for White to win. Black ignored this ko threat.

273-291

Black won by 32.5 points.

It should have been an easy win for Black. The death in the South West was not crucial because Black could have let the group die anyway. The ko was the biggest mistake. Black was lucky White did not have enough ko threats for such a big ko fight.

Brown Stone must allot more time in basic counting before moving on with deeper counting techniques. When Brwnstn is ahead by a large margin, Brwnstn can sacrifice small groups and defend unsecured territories.

END

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