© 2019 Yuan Zhou

Ke Jie vs. Park Junghwan

The Battle to be Number One

Yuan Zhou

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A review of the games of the two best (human) go players in the world with an emphasis on their contrasting playing styles: Ke Jie is an aggressive fighter, while Park Junghwan prefers more solid, territorial plays. They trade being declared the best in the world back and forth.

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About the Author

Yuan Zhou (American Go Association 7 dan) was born in Tianjin, China. Tianjin is a major city in the northern part of China, near Beijing. His father taught him to play go at the age of six, and a year later he won the Tanggu District Junior Go Championship. After this auspicious beginning, Zhou began professional go training while he was still seven years old. He was twice invited to represent Tianjin in the All China Prodigy Cup.

In 1989 Zhou immigrated to the USA, becoming a US citizen and joining the American Go Association (AGA). Zhou was the president of the University of Maryland Go Club, from which he earned a BS in Electrical Engineering, and became increasingly involved in AGA events, winning many go tournaments. Zhou was also elected to the AGA board of directors in 2005.

Zhou is one of the top competitors on the American go scene, winning the Eastern US Open, one of the biggest US tournaments in 1992. He also won the New Jersey Open, one of the biggest US tournaments, four times. Twice he has won the Maryland Open, another major tournament that attracts strong players. Zhou has placed in the top ten in the US Open many times, as well as in the North American Ing Masters Cup and the North American Fujitsu Qualifying Tournament. These tournaments involve the strongest North American go players and include pros. In Zhou’s go career, he has defeated pros many times, including four times in even tournament games: Hak Soo Kim 6p in the 1996 Fujitsu, Xuefen Lin 1p in the 2001 Eastern Oza, Huiren Yang 1p in the 2009 North American Ing Masters, and Feng Yun 9p in the 2011 SAMG World Team Go US Team Qualifier. Zhou also won the US Pair Go Championship four times. Zhou represented the USA in international tournaments many times (WAGC, Korea Prime Minister Cup, World Pair Go Championship, etc).

In 2009, Zhou represented USA in the 4th Korea Prime Minister Cup World Go Championship in Jeonju, Korea and finished in 5th place.

In addition to his competitive successes, Zhou has become a popular teacher and lecturer, frequently giving lectures and teaching lessons at various go clubs in the Eastern US region. He has also published many go books with Slate & Shell (www.slateandshell.com) and SmartGo Books (gobooks.com). Zhou resides in Germantown, Maryland, USA. His website is at www.zhouyuan.com.

Copyright Page

(c) 2019 Yuan Zhou

All rights reserved. Reproduction in whole or in part is prohibited.

Slate & Shell
www.slateandshell.com

Edited by William Cobb

Conversion to SmartGo Books by William Cobb

Table of Contents

Ke Jie vs. Park Junghwan: The Battle to be Number One

About the Author

Copyright Page

Introduction

A Very Recent Game

The chapters in gray are included only in the full book.

The 2018 World Go Championship Game

A Special Game

Shorter Commentaries on Selected Games

Buy This Book

About SmartGo Books

Introduction

Both Ke Jie 9p of China and Park Junghwan 9p of Korea have been rated number one in the world at various times in recent years. Park Junghwan 9p is a bit older, born in 1993, while Ke Jie was born in 1997. At this writing both are still in their twenties.

Ke Jie was rated number one in the world when AlphaGo was being developed and had the “privilege” of losing a three game match to AlphaGo 0–3. (See my book AlphaGo vs. Ke Jie, available from Amazon and SmartGo.) His initial response was to be rather leery of playing AI programs, but he quickly came to believe that he could learn a lot from studying AlphaGo’s games. (Although the AI program has changed its name several times during its development, go players still usually refer to even its latest version, AlphaZero, as “AlphaGo”.) Ke Jie uses AlphaGo’s tactics more than any other top pro, while Park Junghwan stays closer to traditional patterns of play although he also has picked up some of AlphaGo’s moves, as we will see in the reviews of some their games.

At the time of this writing, these two players had played each other in official international tournaments twenty-two times, beginning with a game in the Chinese A League when Park Junghwan was 9p and Ke Jie was only 4p. Park Junghwan was Black and won that game in 2013; while still 4p, Ke Jie won their next two games, first with Black, then with White. With regard to the twenty-two games, each of them has won eleven. But Black has won only four times.

The two have played each other many more times than this, however. Thanks to the internet they have played each other a lot, using internet handles and with very fast time controls, normally ten seconds per move. Fast-play informal internet games between pros have become very common. The players get an idea of various players' styles of play, and they also get accustomed to playing at faster speeds, which is important in the modern world of TV games, which are becoming increasingly important and normally have only two hours basic time, with 30 seconds per move and ten byoyomi periods of one minute. As a result of frequent playing informally on the internet, the quality of play in two hour pro games is remarkably high.

As will become clear in the reviews of their games below, Park Junghwan tends to play more solidly, especially in the opening, is more concerned about the safety of his groups, and is particularly strong in the endgame. Normally, if the game is still even when they reach the endgame, Park Junghwan will win.

Ke Jie is a much more dynamic player. He is especially skilled at middle game fighting and likes to create chaos on the board. He has a much better record playing White than Black. Apparently, he finds the large komi a comforting advantage and plays more freely with White. Because of his love of aggressive attacking and fighting in general, he tends to come out of the opening a little behind. However, since he is regularly rated number one in the world, it is hard to see this as a weakness. Interestingly, Ke Jie has been more successful in international tournaments than in national Chinese events. He has not been rated number one in China as often as Park Junghwan has been number one in Korea. Perhaps the local competition in China is more intense. Before Ke Jie was twenty years old, he won several international titles, including the invitational Bailing Cup and the prestigious Samsung Cup twice as well as the Mlily Cup (defeating Lee Sedol, then number one in the world, in the finals).

Park Junghwan was ranked number one in Korea and in the world before his twentieth birthday. He also has won several international events, including the prestigious Fujitsu Cup before he was twenty.

Here is the complete record of their twenty-two games against each other.

October 10, 2013, Chinese A League. Park Junghwan 9p wins with White.
Score: Park Junghwan 1–Ke Jie 0

September 18, 2014, Bailing Cup semifinal 1. Ke Jie 4p wins with Black.
Score: Park Junghwan 1–Ke Jie 1

September 20, 2014, Bailing Cup semifinal 2. Ke Jie 4p wins with White.
Score: Ke Jie 2–Park Junghwan 1

December 18, 2015, Zhugang Cup. Ke Jie 9p wins with White.
Score: Ke Jie 3–Park Junghwan 1

April 24, 2016, Ing Cup, Park Junghwan 9p wins with White.
Score: Ke Jie 3–Park Junghwan 2

May 16, 2016, Chinese A League, Park Junghwan 9p wins with White.
Score: Ke Jie 3–Park Junghwan 3

June 1, 2016, LG Cup, Park Junghwan 9p wins with White.
Score: Park Junghwan 4–Ke Jie 3

January 30, 2017, Chinese New Year Special, Ke Jie 9p wins as White.
Score: Park Junghwan 4–Ke Jie 4

August 24, 2017, Mlily Cup, Park Junghwan 9p wins with White.
Score: Park Junghwan 5–Ke Jie 4

September 22, 2017, Fenghuang Special, Ke Jie 9p wins with White.
Score: Park Junghwan 5–Ke Jie 5

October 8, 2017, Chinese A League, Park Junghwan 9p wins as White.
Score: Park Junghwan 6–Ke Jie 5

December 10, 2017, Mind Games, Ke Jie 9p wins with White.
Score: Park Junghwan 6–Ke Jie 6

December 15, 2017, Mind Games, Ke Jie 9p wins with White.
Score: Ke Jie 7–Park Junghwan 6

February 2, 2018, Chinese New Year Special, Park Junghwan wins with White.
Score: Ke Jie 7–Park Junghwan 7

March 18, 2018, World Go Championship, Park Jughwan 9p wins with White.
Score: Park Junghwan 8–Ke Jie 7

May, 9, 2018, Chinese A League, Ke Jie 9p wins with Black.
Score: Park Junghwan 8–Ke Jie 8

December 12, 2018, Chunlan Cup, Park Junghwan 9p wins with White.
Score: Park Junghwan 9–Ke Jie 8

January 1, 2019, Chinese New Year Special, Ke Jie wins with Black.
Score: Park Junghwan 9–Ke Jie 9

February 2, 2019, Chinese New Year Special, Park Junghwan wins with Black.
Score: Park Junghwan 10–Ke Jie 9

March 20, 2019, World Go Championship, Park Junghwan wins with Black.
Score: Park Junghwan 11–Ke Jie 9

May 14, 2019, IMSA Elite Mind Games, Ke Jie wins with White.
Score: Park Junghwan 11–Ke Jie 10

July 18, 2019, Shangyu Go Tournament, Ke Jie wins with White.
Score: Park Junghwan 11–Ke Jie 11

A Very Recent Game

I’d like to start with this recent game between Ke Jie 9p of China and Park Junghwan 9p of Korea in the invitational 7th Chinese New Year Special Tournament, number 19 on the list of their official games. This game, which was the final of the event, was played on February 2, 2019. Ke Jie was White this time. He has been nearly invincible with White in recent play. The time limit in this game was only two hours so moves were played at the rate of thirty seconds with ten byoyomi periods of one minute. Since this time limit has become popular with the demand for live TV broadcasts, pros have been training extensively in order to play well under this time system. Komi is seven and a half points. Park Junghwan is Black. Black had won the previous game, but only twice in the fifteen games before that. This is their nineteenth game.

Moves 1–4

＞＜ ▶︎

AlphaGo’s influence on the pros has led to the nirensei (two star points) opening becoming very popular for Black, which is a big change from recent practice. White also plays the nirensei, which has been the most popular opening for White for a long time now.

Moves 5–6

＞＜ ▶︎

In the past, White would usually slide to A or pincer at B in response to the approach at Black 5. The kick with White 6 is another new idea learned from AlphaGo, still considered bad by many players, …

Moves 7–8

＞＜ ▶︎

… because it seems to help Black and the corner is still open. It does prevent a black invasion at the 3–3 point or attachment at A.

Moves 9–10

＞＜ ▶︎

Black is happy with this result after 9. There is still aji in the lower left corner. White must decide when and how to fix this. In the past, White would usually approach the lower right corner at A in this situation to deter a black moyo, but Ke Jie uses a popular AlphaGo tactic and makes an early invasion on the 3–3 point with White 10.

Moves 11–12

＞＜ ▶︎

This also seems to help Black. It is easy for him to decide the direction for 11. Black gets a large potential territory at the bottom, though it can be invaded, of course. White could get the two corners, but together they would be smaller than Black’s bottom area if it all becomes territory. However, White does not intend to let that happen. See the next three variation diagrams.

Variation

＞＜ ▶︎

In the past, play might continue this way. After Black 7 and 9, the bottom area becomes solid territory for Black. However, White is not going to play this way these days. AlphaGo has shown that White 6 is not good. White will no longer play that way so as to leave the bottom area open to invasion. As a result Black will not play this 1.

Variation

＞＜ ▶︎

Instead of White 6 in the previous diagram, White would take sente to play elsewhere and plan to later play something like 1 and 3 in this diagram. Of course, White needs to understand how to handle this situation. (See my book: Playing AlphaGo’s Early 3–3 Invasion.) So Black will not play 1 in the previous diagram.

Variation

＞＜ ▶︎

Black could play 13 in the game at this 1, but White would respond at 2 and this would become even more complicated. Nevertheless, this is a playable option for Black.

Moves 13–14

＞＜ ▶︎

In the game, Park Junghwan plays this 13, which is the simplest choice and aims to get sente, although it puts the least pressure on White. So White slides to 14 and is happy with this result: White takes the corner and prevents Black from sealing these white stones in. Also, Black’s bottom position is not yet solid territory.

Moves 15–16

＞＜ ▶︎

Naturally, Black now approaches in the upper left and White makes a normal response with 16.

Traditionally, Black might respond at A or slide to B, or nowadays attach at C.

Move 17

＞＜ ▶︎

However, nowadays, Black can see those responses in the previous diagram as not enough to make up for the large komi. So Black directly attacks White at 17. White’s shape in the lower left corner is thin, especially with the peep at A for Black. A good local response to Black 17 for White would be at B, protecting against both Black A and a black peep at C, but that would put no pressure on Black who could easily settle down at D.

Moves 18–20

＞＜ ▶︎

In the past, White 18 would be seen as bad: attaching to a weak stone. However, AlphaGo has made players see that there is more freedom in go than was appreciated earlier. White seeks a better way of defending his weakness in the corner.

Black 19 is a normal response. Naturally, White stands up with 20.

Variation

＞＜ ▶︎

If Black extends at 1 now, White would be happy to block at 2, making his corner secure. An extension by Black at A next, to protect his cutting point, would be gote. Black cannot push out from Black 1 and cut White because of his own cutting point.

Moves 21–23

＞＜ ▶︎

Black 21 is a tesuji that protects Black’s own cutting point and opens up White’s corner area (a good move to remember).

White blocks with 22 to protect the corner, although there is still aji there.

Black could simply extend at A to settle with 23, but White would take sente. So Black seeks sente by extending out.

Moves 24–25

＞＜ ▶︎

White keeps the pressure on Black with the hane at 24, and Black responds by cutting with 25. Neither player wants the other to get sente easily. Black can fight this way because his position at the bottom is strong and White’s corner still has problems. A fighting game gives Black more chances to overcome the komi.

Moves 26–29

＞＜ ▶︎

Both players make normal extensions with 26 and 27. Black blocks with 29 to prevent White from playing at that point. This also keeps the pressure on White’s corner which still has inside aji.

White must defend with 28 but after Black 29, White’s corner is still not settled. If White now fixes the corner, Black will extend on the upper left side.

Moves 30–32

＞＜ ▶︎

Since White does not want to leave two stones floating on the outside, he first attacks Black with 30.

Black defends with 31, but neither of the two groups in the lower left is alive yet. After White 32, Black must do someting to help his group. He cannot allow White A now.

Moves 33–35

＞＜ ▶︎

Park Junghwan prefers to avoid aggressive fighting, which is risky, while Ke Jie thrives on it.

Black 33 is the defensive tesuji Black was aiming for. Naturally, White aims to cut Black off with 34, but Black then clamps with 35. This will allow Black to get out with his group.

Moves 36–38

＞＜ ▶︎

White captures a stone with 36, but Black can still get this group out. White cannot prevent that yet.

So Black attacks the corner with the clamp at 37. If Black captures , his group will be alive, and there will be no need to run out. White cannot allow that, hence 38. White could peacefully live with 38 at A, but that would lose the purpose of his attack on Black.

Moves 39–41

＞＜ ▶︎

White’s corner still has problems (Black A can kill it), but now Black must save his group by getting out, starting with 39.

White moves out with 40. He does not cut at B because that would be too dangerous with his corner unsettled. He is giving up the attack on Black’s group here and Black makes the group safe with 41.

Moves 42–45

＞＜ ▶︎

White settles the corner in an efficient way.

Black uses sente to play 45 in the center, creating a strong group.

An analysis with the Chinese go AI program “Fine Arts”, which is based on the AlphaGo program, shows that at this point, the opening is good for Black. But Black has not won the game yet, of course.