This EPUB is provided without Digital Rights Management (DRM), allowing you to read it on your EPUB reader of choice. We trust that you use this EPUB file for your personal use only. Buying the book at gobooks.com ensures that authors and publishers get paid, and makes it possible for us to convert more books to digital format.

This EPUB contains static go diagrams only. This makes it compatible with more EPUB readers, but does not show the full potential of interactive Go Books. Get a download link for the interactive version at gobooks.com/support.html.

© 2018 Yuan Zhou

Rethinking Opening Strategy

AlphaGo’s Impact on Pro Play

Yuan Zhou

Buy the full book at gobooks.com

The AI program AlphaGo Zero has introduced several new ideas about how to play in the opening of a game of go. Yuan Zhou, a popular go teacher, discusses several of them and shows their use in several pro games.

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). He earned a BS degree in electrical engineering at the University of Maryland, where he was the president of the University Go Club. He also became increasingly involved in AGA events, winning many tournaments. Zhou was also elected to the AGA board of directors in 2005 and is currently president of the XYZ Go Club, an official AGA chapter.

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 prestigious New Jersey Open, another of the biggest US tournaments, four times. Twice he won the Maryland Open, another major event that attracts strong players. These tournaments involve the strongest North American go amateurs as well as pros. In Zhou’s go career, he has defeated pros many times, including five 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 and the 2014 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 (World Amateur Go Championship, Korea Prime Minister Cup, World Pair Go Championships, etc.).

In 2009, Zhou represented the USA in the 4th Korea Prime Minister Cup World Go Championship in Jeonju, Korea, and finished in fifth 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 regions well as on the internet. He has also published many go books with Slate & Shell and SmartGo E-Books (www.smartgo.com). Zhou resides in Germantown, Maryland. His website is at www.zhouyuan.com .

Copyright Page

(c) 2018 Yuan Zhou

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

Slate & Shell
1425 Westshire Lane
Richmond, VA 23238
www.slateandshell.com

Edited by William Cobb

Cover design by Laurie M. Crammond

Conversion to SmartGo Books by William Cobb

Table of Contents

Rethinking Opening Strategy: AlphaGo’s Impact on Pro Play

About the Author

Copyright Page

Introduction

Opening Ideas that AlphaGo Has Made Popular

1. The Corner Enclosure

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

2. Responding to a Low Approach Move

3. A Well-Known Joseki Following an Opening with Alternating 3–4 Point Stones

4. The 3–3 Point Invasion Under a 4–4 Point Stone

5. Responding to a Ladder Breaker

6. Another 3–3 Point Invasion Situation

7. Starting on a 3–3 Point

8. Continuing After an Approach to a Corner 4–4 Point Stone

Professional Games Incorporating AlphaGo’s New Moves

Game 1

Game 2

Game 3

Game 4

Game 5

Game 6

Game 7

Game 8

Game 9

Game 10

Game 11

Buy This Book

About SmartGo Books

Introduction

An important factor to remember in analyzing AlphaGo’s moves is that they are the result of an incredible amount of actual play. The program has played millions of games against itself, thus gaining an amount of experience that is not possible for a human player. So the AI program’s latest version, AlphaGo Zero, has acquired its understanding of the game in the same way that humans do—through playing. Thus, when it adopts ways of playing that are similar to those humans believe to be best, this is a striking endorsement of the correctness of the human understanding. A simple example of this is starting the game by first playing in the corners and then playing on the sides before playing in the center. Some might have expected the AI program to adopt a novel approach, such as starting with a play in the center. The fact that that has not happened is significant. This also supports the ancient notion that the only effective way to learn how to play go and to improve as a player is to actually play, as much as possible. The possibility of playing frequently on the internet is one of the reasons behind the recent phenomenon of professionals becoming so strong at a young age.

The fact that the ultimate version of AlphaGo, AlphaGo Zero, started with only the rules and no input of human game records, let alone human guidelines about best ways to play, and, after playing a enormous number of games, is able to consistently defeat earlier versions of the program, strengthens confidence in the significance of the general patterns of play that AlphaGo Zero has adopted. The AlphaGo team claims that there is no reason to think that AlphaGo Zero reached the highest possible level of play before the need to use its computers for other purposes forced them to shut down the program. But what it has learned about playing the game is consistent with a lot of the understanding humans have developed over several thousand years and is also strikingly innovative in a number of ways, which is very exciting for human players. So AlphaGo Zero has shown that humans have been on the right track in their efforts to understand go and has also provided us with new ideas for study for a long time.

An important point to remember in studying AlphaGo’s moves is that the program is very strong in terms of whole board awareness. As a result, in studying local patterns we must take into account that it is not obvious just what whole board possibilities AlphaGo is taking into account. This is why a lot of study of AlphaGo’s moves is necessary. Nevertheless, it is clear that some of AlphaGo’s moves in the opening definitely offer improved possibilities. In trying them out, just don’t forget the importance of paying attention to the whole board situation. Do not just randomly try these moves.

Another positive consequence of AlphaGo has been to encourage more humility in our approach to go. Some top players were beginning to think they were very close to mastering the game in a complete way. We know that is not the case now. In fact, there is now even more reason to believe that the game is in principle incapable of being totally mastered. There may not be a way of playing that can guarantee victory.

One other point I would like to note is that AlphaGo confirmed the accuracy of many of Go Seigen’s ideas about the best way to play, and Go Seigen’s play at his peak was strikingly similar to that of AlphaGo. Go Seigen died a few years before AlphaGo was created. Perhaps his spirit somehow managed to infiltrate the AI program.

Yuan Zhou

January 2018

Opening Ideas that AlphaGo Has Made Popular

1. The Corner Enclosure

Ever since the Japanese developed territorial style play, the corner enclosure in the upper right of this diagram, made with a 3–4 point stone and a small knight’s move slide, has been judged to be the best play in the corner. Of course, back in the twentieth century, Go Seigen said that this was an inefficient shape and should be abandoned in favor of the corner enclosure with the large knight’s move slide in the lower left corner of this diagram.

AlphaGo clearly agrees with Go Seigen about this. After starting in a corner with a 3–4 point stone, AlphaGo consistently plays the large corner enclosure or else a two space high extension as in the upper right corner of this diagram—the latter is very popular nowadays. A problem with the small enclosure is all the contact moves that the opponent can make against it: For example, A through F in the lower left corner of this diagram. When Black responds to these contact moves Black’s position quickly becomes over-concentrated.

Go Seigen also saw the possibility of a shoulder hit at A in this diagram as a weakness of the small corner enclosure. Actually, Go Seigen strongly encouraged playing shoulder hits as the maximum way to compress an opponent’s position without directly invading. As opposed to an invasion, this play lowers risk and offers a trade of the corner for outside influence. This also fits with the fundamental principle of go that you do not try to destroy your opponent and get everything, but simply to play better than the opponent so as to get a little more. AlphaGo also often plays shoulder hits, again agreeing with Go Seigen, and this shoulder hit against the small corner enclosure has become popular, appearing in serious games at the top level.

This position is slightly different, but AlphaGo also often plays this shoulder hit against the small knight’s move slide from a 4–4 point stone. In the past, this was an unusual play, rarely seen, especially early in the game, which is when AlphaGo often plays it. It doesn’t seem urgent and is not sente, but AlphaGo plays it often. The idea is the same as in the above case, and this move has also become popular in pro play. Admittedly, AlphaGo had a good success with this move more consistently than humans have, but many players are trying it.

Among human players, the two space high extension from the 3–4 point stone in the upper right corner is now more popular than the large knight’s move slide. This is because it is a way to avoid the shoulder hit. This was considered bad in the past because it makes the corner more vulnerable, but it fits a greater concern for the center, which is characteristic of AlphaGo’s play.

Moreover, AlphaGo makes this contact play against the large knight’s move slide at White 1. Although it certainly looks odd at first to traditional players, this move has also become very popular, which encourages interest in the straight extension. (At first you might think this White 1 is a beginner’s move.) Black has to decide whether to defend the corner at A or play outside at B.

If Black defends the corner with 2, White will hane at 3. Both players have cutting points, but this was Black’s corner initially so he wants to avoid trouble here. A confusing fight here would be good for White.

A good defense by Black would go this way, and at this point it may look very good for Black. AlphaGo’s continuation as White may be difficult for most players to find.

The cut with White 7 is AlphaGo’s move. It may be hard to find because it looks like suicide, but this is actually advanced level play.

Of course, Black can capture White’s invasion with 8, but White’s aim is to make 9 sente.

After Black captures with 10, White gets to make the very nice extension to 11. So White gets a good position on the upper right side. Of course, White’s position may not be entirely equal to Black’s corner, but remember that Black had two moves in this corner before White played. This is a very efficient way for White to play against the corner enclosure with the large knight’s move slide. So, as Black, AlphaGo does not play the atari at Black 8 in this sequence.

After White cuts on the inside with 7 in this situation, AlphaGo turns at Black 8, denying White the sente move here. This is fighting hard, but now Black’s corner has a problem.

White can continue in the corner this way. After White 11, White can live in the corner, but at this point, White doesn’t yet have enough liberties on the outside in this fight.

After Black 12, if White plays 13 to live in the corner, Black can damage the outside severely. So White must first do something on the outside before playing 13.

So White will continue this way with 9 (this is AlphaGo’s move), and Black is still missing a move in the corner. However, if Black fixes the corner with 10, White gets a very nice shape on the outside with 11.

So, not wanting the result in the previous diagram, Black pushes out with 10, which is sente because it threatens a push and cut on the outside.

White protects with 11. Black can push with 12 and peep with 14 in sente. However, after that, Black must come back and protect in the corner with 16. Black gets the corner, but all of White’s moves are on the outside, which is usually better in the opening. So this sequence is a gain for White—especially given that Black had two moves here to start with. This would be especially significant if Black was building a moyo on the right side or in the center. This sequence has become a sort of “AlphaGo joseki”. It is being tried often in pro games. The key, of course, is how it works with the particular whole board situation.

If Black doesn’t like this result, (not wanting to give White all these outside moves that damage Black’s potential), Black can play 2 on the outside. White will then go into the corner. Black can seal White in but cannot cut White off at A after White 7.

If Black tries to cut White off with 8, there is a double atari at A after White 9.

So Black must block on the outside. After White pulls back with 9, Black must prevent White from cutting at Black 10. This means White is already alive in the corner in sente! And Black already had two moves in this corner.

This result is definitely very good for White. You can see why the attachment with White 1 in this sequence is now very popular and why the two space high extension from the 3–4 point stone instead of the large knight’s move slide is also very popular, even though it leaves the corner open.

Professional Games Incorporating AlphaGo’s New Moves

Game 1

Now that AlphaGo has been established as the strongest go player ever, top pros around the world are regularly incorporating some of the AI’s distinctive opening moves into their games. Ke Jie 9P of China, who is ranked number one in the world and played a three game match against AlphaGo, uses AlphaGo’s new ideas more than any other pro. A good example is his recent match against Iyama Yuta 9P of Japan (the top Japanese pro) in the semi-finals of the international LG Cup on November 15, 2017. In this game, Ke Jie is White and Iyama Yuta is Black.

Moves 1–4

Iyama begins with the very common pattern of a 4–4 point stone and a 3–4 point stone with the weak side defended by the 4–4 point stone.

Ke Jie, on the other hand, starts with an opening that has not been seen in many years in pro games: two 3–3 point stones. Playing on the 3–3 point in an open corner was popular for a while about fifty years or so ago, but had fallen out of favor as too slow. Before AlphaGo, pros would not play even one, let alone two such moves. Even amateurs have generally stopped playing this move.

As I noted earlier, one of the advantages of this move is that it avoids the problems AlphaGo has revealed that can follow from starting on a 4–4 or 3–4 point in the corner. However, it is still startling to see such an opening in a very serious game in a major international tournament. This game is not a casual exercise. An enormous amount of prestige and money are at stake in this game. These two players are number one in their respective countries and the game is being played in Tokyo, Japan.

Moves 5–7

Iyama sets up the high Chinese opening with Black 5, and Ke Jie makes a normal approach move with White 6.

Black 7 is a normal play in the high Chinese opening.

The normal response now by White in this situation would be an extension at A or a slide to B, but Ke Jie now makes another AlphaGo opening move.

Moves 8–10

Namely, the attachment with White 8, which has become very popular. Playing Black 9 and White 10 is now the normal continuation. After this Black has a choice of playing at A or B, taking the inside (the corner) or the outside. This early in the game, it is normal to give higher priority to the outside.

Moves 11–13

So Iyama plays Black 11 and 13, giving White the corner.

Black does not connect at A with 13 since that would allow White to take the corner and come out on the top side. But this leaves Black with two cutting points on the outside.

Moves 14–15

Naturally, White contends for the outside by cutting at 14, which forces Black to save his two stones with 15.

Now White needs to make sure he can live in the corner.

Moves 16–18

White makes the corner safe with 16 and 18.

Now Black needs to help his three stones that are in danger of being sealed in. Cutting at A would start too messy a fight at this early stage.

Move 19

Black plays atari at 19 to get out at the top.

So White has taken this corner in sente and there is significant aji for White on the outside here now. If White connects at A later, it will not be easy for Black to kill these stones.

Move 20

Ke Jie then plays a reducing move against the high Chinese opening with 20.

At this point in the opening, Ke Jie has the lead in the game. However, he makes a mistake later that Iyama Yuta is able to capitalize on and Iyama wins the game to reach the finals.

This move of AlphaGo’s against a 4–4 point stone is certainly an interesting one and it is getting a lot of study. And of course starting with 3–3 point stones is a virtual revolution.

Buy This Book

Buy the full book at gobooks.com

© 2018 Yuan Zhou

This edition includes both the English and Spanish text.