Weird and Wonderful

Volume 2

Unusual Opening Patterns and Techniques through the Eyes of AI

by Kim Ouweleen

Kiseido Publishing Company
Chigasaki, Japan

Buy the full book at gobooks.com

Joseki and go techniques are subject to change. They evolve and are refined over time in the constant search for perfection. Since AI has come onto the scene, joseki and superhuman computer-go programs have become inseparable. We can no longer play the sequences that were familiar to us without wondering what AI has to say about them. Many established corner patterns have recently been refuted, and some lesser-known ideas have risen to the surface and become the new standard.

This book brings together a range of unusual opening patterns, tested against AI. Inside, you will find cherished techniques from the past that AI has overturned, alongside fresh innovations and rare variations now confirmed as sound. In the Weird and Wonderful series, the extraordinary is never far away: feed the tiger on the first line, meet the monkey jump’s big brother, break through your opponent’s wall with three unstoppable moves, rediscover the once-forbidden hane, and explore Korea’s traditional sunjang baduk from a modern perspective. If you are curious about AI go and eager to surprise your opponents, this is the book for you.

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Copyright Page

Weird and Wonderful, Volume 2
Unusual Opening Patterns and Techniques through the Eyes of AI

by Kim Ouweleen

Copyright © 2025 Kim Ouweleen
Book design by Justyna Klęczar
Cover design by www.murugandi.com

All rights reserved according to international law. No part of this book may be reproduced by any mechanical, photographic, or electronic process, nor may it be stored in a retrieval system, transmitted, or otherwise copied for public or private use without the written permission from Kiseido Publishing Company.

Published by
Kiseido Publishing Company
Kagawa 4–48–32
Chigasaki-shi, Kanagawa-ken
Japan 253–0082

ISBN of the printed version: 978–4–906574–95–7

Converted for SmartGo Books by John Mifsud.

Contents

Weird and Wonderful, Volume 2

Unusual Opening Patterns and Techniques through the Eyes of AI

Copyright Page

Preface

About the Author

Sunjang Baduk

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

An Alternative Atari

A Trick Move Against the Sanrensei Opening

The Forbidden Hane

Plunging into the Deep

A Mesmerizing Miai Invasion

A Mesmerizing Miai Invasion II

Tickling the Underbelly

AI’s Submarine Pincer

Peeking Around the Corner

Punishing a Classic Overplay

A Rare Follow-Up to a Common Joseki

How to Trap a Crawler

Feeding the Tiger on the First Line

The Gorilla Jump

A Technique to Avoid Confinement

Reevaluating a Sabaki Technique

Nothing Is What It Seems

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Preface

Joseki and go techniques are subject to change. They evolve and are refined over time in the constant search for perfection. Since AI has come onto the scene, joseki and superhuman computer-go programs have become inseparable. We can no longer play the sequences that were familiar to us without wondering what AI has to say about them. Many established corner patterns have recently been refuted, and some lesser-known ideas have risen to the surface and become the new standard.

In this book, I explore a range of unusual opening patterns and techniques, tested against AI. As was the case for part one of Weird and Wonderful, I focus on the extraordinary: moves that surprised and inspired me.

For the AI analysis, I consulted the strongest version of the program KataGo available at the time of writing. Although there is a trend for it, I have chosen not to specify percentage or point gains/losses in the AI’s evaluation of moves. The reason for this is that such numbers fluctuate based on the computer’s processing power and the time or number of playouts allowed, making them potentially misleading.

In general, I have striven to include the optimal AI lines for the patterns that I analyze. AI, however, has a logic of its own; it can complicate matters to such an extent that writing about them no longer makes sense. In certain positions, such as those from professional games, KataGo may suggest a variation tailored to that specific configuration but irrelevant to the topic I am discussing. In such cases, I exclude those variations and instead focus on sequences that I deem more repeatable or more reasonable to the human eye. Since the optimal local move often depends on the overall board position, I examine joseki and techniques in this book from multiple perspectives.

A mistake in the eyes of AI does not always translate to an error for a human player. Small inefficiencies add up for a computer but are generally negligible to humans. In some cases, a ‘bad move’ can serve a strategic purpose — for example, to counter an opponent’s moyo aspirations, as shown in the chapter ‘A Trick Move Against the Sanrensei Opening’. In other cases, suboptimal moves can simply be fun to play.

Several chapters in this book could be considered a final tribute, a farewell of sorts, to old patterns that have been debunked by AI, such as ‘Reevaluating a Sabaki Technique’. Other chapters bring forth new inspiration from AI innovations, like ‘An Alternative Atari’, and ‘The Forbidden Hane’. More than just a collection of AI moves, Weird and Wonderful 2 contains brilliant human ideas that have survived the test of time. Most satisfying to me, personally, are the instances in which rare patterns developed through human ingenuity are confirmed by AI: striking examples of this are the chapters ‘A Technique to Avoid Confinement’, ‘The Gorilla Jump’, and ‘Feeding the Tiger on the First Line’.

Writing this volume was a bittersweet experience, reminiscent of the emotions I felt when AlphaGo defeated Lee Sedol in 2016: a sinking realization that some of the mystique and romantic charm of go has been lost, combined with the excitement for fresh ideas and unopened doors waiting to be explored.

Over the years, I worked together with many professional go players who have contributed to the content in this series. For volume two, I would like to express my gratitude to Alexander Dinerchtein 3-dan, Kim Seong-rae 8-dan, Baek Ji-hee 2-dan, Cho Hye-yeon 9-dan, Yoon Young-sun 8-dan, Yan An 7-dan, Nam Chi-hyeong 1-dan, and Kim Young-sam for their expertise and keen eye for the extraordinary.

Richard Bozulich, Peter Brouwer, and Justyna Klęczar were instrumental in the proofreading process: thank you for your extensive corrections and suggestions.

Justyna Klęczar deserves a paragraph of her own. She came to my rescue and designed the book in LaTeX when I was down in the pits of despair. Justyna, thank you for your eternal patience and for being there when all else failed. You are amazing.

Kim Ouweleen
September 2025

About the Author

Kim Ouweleen is an author, graphic designer and go teacher from Amsterdam, the Netherlands. He has made numerous go-related artworks under his artist pseudonym Murugandi. Kim has worked for the European Go Cultural Center and the European Go Journal, and has created video content for EuroGoTV and BadukMovies. He previously authored the 2016 European Go Yearbook, and co-wrote Weird and Wonderful, Volume 1: Extraordinary Moves by Professional Go Players. His playing level is 4-dan.

Sunjang Baduk

Dia. 1

Sunjang baduk (순장바둑) is a traditional Korean variant of go that is known to have been commonly played in the country from the 16th century until the first half of the 20th century, though some evidence suggests it may have much older origins. Its last official game record dates to March 1937, played between No Sa-cho and Chae Geuk-mun (published in the Chosun Ilbo newspaper). The variant became virtually extinct with the outbreak of the Korean War in 1950. Sunjang baduk’s main distinction from contemporary go is the starting position of the game: it has a predetermined opening consisting of 16 stones that are symmetrically placed around the board. Black then plays the first move, traditionally on the central point: see Dia. 1. The intersections on which the stones are placed for the initial set-up are known as hwajeom (화점, ‘flower points’), named after markings in the shape of flower petals that classical sunjang baduk boards have to indicate these points. They are also referred to as ‘guard points’, perhaps because of a military connotation of the term sunjang, which is shrouded in mystery; the prevalent way to write ‘sunjang’ in characters translates to ‘touring officer’, a guard who moves from post to post. This may be linked to the stones that are posted round the board at the start of the game.

Evidence suggesting ancient origins of sunjang baduk includes a luxurious 7th-century go set known in Korea as Mokhwajadangiguk (목화자단기국), that is housed in the Shōsōin repository in Nara, the imperial treasury of Japan. The board features the 17 flower points characteristic of sunjang baduk, is made from red sandalwood, with inlaid ox horn and golden details, and is equipped with intricately carved ivory stones. According to historical records, the go set was likely a diplomatic gift from king Uija (599–660 AD), last ruler of the Korean kingdom of Baekje, to Fujiwara no Kamatari (614–669 AD), the most influential Japanese aristocrat of his time.

Dia. 2

Sunjang baduk shares some similarities with Tibetan go. Tibetan go also starts with a fixed opening pattern of alternating black and white stones, but on the third line of a 17 by 17 board instead, with White having the first move: see Dia. 2. One could argue that in sunjang baduk White plays first as well, as Black’s move on the 10–10 point is expected (it is marked with a flower on old Korean boards) and therefore, in a way, part of the set-up.

Dia. 3

In classical Chinese go, White starts after a diagonal placement of two black and two white stones on the 4–4 points: see Dia. 3. It is likely that both Tibetan go and sunjang baduk are derived from the classical Chinese set-up.

Another distinguishing characteristic of sunjang baduk is its method of counting. The game ends after all neutral points are filled; ‘neutral points’ is, however, an unsuitable term in the case of sunjang baduk since they can contribute to the score. When counting starts, all prisoners are ignored. Dead stones inside territories are removed and ignored as well. All stones that are not forming part of the outside walls (‘superfluous’ stones inside territories) are removed, leaving the bare minimum stones needed to encircle the territories; cutting points can be left at this stage, as long as no stones are left in atari. Finally, the empty intersections are counted up. The player with the most points wins.

Traditionally, there was no komi, giving Black a large advantage. Similar to Chinese rules, playing inside your own territory does not cost you points.

Below is an example of this counting method on a 9 by 9 board. The position is taken from a game played by Murakawa Daisuke 8-dan (Black) and Iyama Yuta 9-dan in May 2013.

Dia. 4. End of the game

Step one: territories have been divided and all ‘neutral points’ have been occupied.

Dia. 5. Removing dead stones

Step two: dead stones inside the territories are removed.

Dia. 6. Removing surplus stones

Step three: internal superfluous stones are removed, without leaving stones in atari. Counting can begin: Black has 20 points and White has 17 points. Without komi, Black wins by 3 points.

Historically, it is ambiguous whether Dia. 5 and Dia. 6 should be regarded as separate steps. It is possible that they were executed at the same time, by removing dead stones of the opponent and internal superfluous stones together.

Sunjang baduk is a unique and challenging way to play go, since it starts from an opening position that is unfamiliar to most go players today. Knowledge of modern opening theory is largely inapplicable to it. Because the board is evenly divided by stones that have a pressing impact on each other, players find themselves thrown directly into a middle game full of fighting.

Let’s analyze sunjang baduk with AI to discover some of its own joseki and opening techniques. For the sake of simplification, I will disregard traditional sunjang counting. Komi has an impact on the AI evaluation; the following board positions are analyzed from a modern point of view, with a compensation for White of 6½ points.

Dia. 7. White is ahead

When the board is empty, AI assesses White to be slighly favorable at circa 52.6%.

Dia. 8. Similar win-rate

When starting from the symmetrical sunjang set-up, it is perhaps not surprising that the estimated win-rate stays roughly the same. AI seems to indicate that this position is fractionally worse for White than Dia. 7.

Dia. 9. Breaking with tradition

There is a classic go proverb that teaches us: ‘when right and left have the same shape, there is a play in the center.’ In this light, Black’s traditionally prescribed move at A makes sense. It strikes at the heart of the symmetrical position and impacts all stones on the board. Interestingly, AI disagrees with A and assesses it as a small mistake. Instead, it suggests Black to play at 1, B, or C.

Dia. 10. Symmetry

Sunjang baduk would not be the same without Black 1, so let’s continue our study from this established position. AI still deems it paramount to seal off the corners, and by that logic White 2 to Black 5 follow. These diagonal moves do not only strengthen the corners by preventing the 3–3-point invasion, but also take away eye space for the marked stones. Furthermore, they look underneath the marked stones, providing a lifeline to nearby allies.

Dia. 11. Attachment

How can one follow up to exploit these corner shapes of the opponent? One of the main variations AI recommends is to attach at White 1 and create light shape towards the center with the moves to 5. By moving into the center, White strenghtens his lower side and simultaneously weakens the marked stone.

Dia. 12. Miai invasion

Another option for White is to invade at 1, a move that I discuss in more detail in the chapter ‘A Mesmerizing Miai Invasion’. Black plays 2 to prevent White from linking up, and White makes life in the corner with the sequence to 9. Black can continue with a move like 10, which sets up a large framework. Note that White has a sente move at A to support his vulnerable marked stone.

Dia. 13. Second invasion

A second, more direct way to invade the corner is White 1 to 5. After Black 6, White is not yet fully alive. However, AI recommends White switch to the left side and play the attachment at 7. This move looks to sacrifice the marked stone in good style. Here, too, depending on Black’s continuation, White may want to utilize the aji on the second line at A.

Dia. 14. Reducing the corner

Instead of Dia. 10, what happens if the corners are not reinforced? When White plays 1, Black attaches at 2 and can reduce the corner in sente while isolating the marked stone.

It is notable that both the AI recommendations of White 1 and Black 6 are moves on the seventh line. In sunjang baduk, AI seems fond of such moves and suggests them in various variations. Remarkably, handicap play in sunjang baduk is traditionally arranged by placing additional stones for Black on the seventh line. White then occupies the center point: see Dia. 15.

Dia. 15. Handicap set-up

In sunjang baduk, a one-stone handicap is arranged by Black placing a stone on the center point and then playing on any intersection of choice. For two- to eight-stone handicaps, White occupies the center point instead and Black places the handicap stones as follows:

2 stones: on G, C.
3 stones: on C, G, E.
4 stones: on A, C, G, E.
5 stones: on A, C, G, E, D.
6 stones: on A, H, G, C, D, E.
7 stones: on A, H, G, C, D, E, B.
8 stones: on all letters.

White then has the first move.

Dia. 16. Settling technique

After the attachment in the corner in Dia. 14, it is good to know that Black has a local technique that can be used to settle quickly when in danger. Instead of Black 4 in Dia. 14, Black may play 1 and the two-step hane of 3. The timing of the peep at 7 is exquisite, and with 9 and 11 Black sets up a base.

Dia. 17. Cross-cut variation

If White wants to avoid the scenario of Dia. 14, after Black’s attachment in the corner he can play the hane on the outside at 1. Black will cross-cut at 2. The AI sequence continues with the moves to 23.

Black can keep things simple by playing the cross-cut of Black 2 at White 3 instead and take the corner, but it is not the best variation according to AI.

Dia. 18. Outside is king

When playing sunjang baduk, it is not advisable to invade the corners straight away. Black can make life with moves 1 to 11, but White’s thickness on the outside is superior. White 12 radiates. It protects against the black cut at A, neutralizes the marked stone, and has a significant impact on the center.

Dia. 19. In preparation of 3–3

Let’s look at some other opening moves that AI suggests. After White 1, Black 2 is one of the main points that AI is interested in. If White does not defend the lower right corner, Black will invade at 4.

Dia. 20. Black takes the corner

White blocks at 1 and Black pushes at 2. White must be careful because of the presence of Black’s marked stone. White 3 is a safe continuation. The sequence to 15 follows, with Black strengthening his group at the bottom and White reinforcing his group on the right. Next, Black can launch a splitting attack with a move like A.

Dia. 21. White is in trouble

Instead of White 3 in Dia. 20, White 1 here would necessitate extreme caution. After Black 2, White can no longer respond by blocking at 3: Black 4 to 14 split and weaken the white stones on the right side.

Dia. 22. The safe way

To avoid the complications that come forth from Dia. 19, AI recommends that White defend at 2. Black 3 is a follow-up that keeps the aji in White’s corner alive. White then plays 4 to reinforce his stone on the lower side or, alternatively, defends at A to solidify the corner, followed by a black cap at 4.

Figure 1. Capping moves (1–2)

Capping moves are to be anticipated in sunjang baduk, and there is an interesting twist to dealing with these moves that goes against the dogma. Here we have an example, the start of a game between Lee Chang-ho 7-dan (Black) and Cho Namcheol 9-dan that took place in October 1995. Black played in the center and White capped at 2.

Dia. 23. Shoulder hit on the seventh line

In response to White’s capping move, AI surprisingly recommends Black’s shoulder hit at 1, another move on the seventh line. AI’s inclination is to continue with a white attachment at A, leading to complications. If White plays the natural-looking defense at 2 instead, also a fine move according to AI, Black continues with a knight’s move at 3. This shows the importance of the center.

Figure 2. Sabaki (3–5)

In the game, Black continued with 3 and 5, a standard technique to move out in good shape and split the white stones.

Dia. 24. Dogma

Dogma prescribes that White should play the hane at 1 and that Black 2 is the proper response. This shape is often used in go books as an example of an empty triangle that is good, rather than bad. In this position, however, AI has a different plan in mind.

Dia. 25. The sunjang way

Instead of the empty triangle, AI wishes Black to block at 1. White connects at 2 once again, and the moves to 11 follow.

Dia. 26. Center is paramount

The danger of the black block at 1 is the atari at 2, followed by White 4, cutting off the black stone at the bottom. Dia. 24 is traditionally considered the correct way to play, as it focuses on keeping Black’s stones connected. In this case, however, Black does not mind being split: the moves to 8 are good for him. In sunjang baduk, power in the center has a big influence on the rest of the board. Black’s ponnuki is of more value than White’s territory at the bottom, which is still open to an invasion at A.

Figure 3. Ahead of his time (6)

Cho did not play the white hane but bumped at 6 instead. AI confirms that this is the best move. Black should continue by playing at A.

Dia. 27. The other cap

Let’s take a quick look at another capping move: White 1. How should Black respond?

Dia. 28. Attach and conquer

Although the knight’s move at A is not a bad move, AI highlights the attachment of Black 1, towards the side of the white corner in the upper left.

Dia. 29. Cap into cap

White’s best local response is 1, followed up by a second cap at 3. Black 6 and 8 keep things clear. Instead, Black could play 6 at 7 as well, igniting a running fight and setting the board on fire.

Figure 4. Dawn of a new era (1–18)

As a curiosity, have a look at the opening moves of this Japanese pro game. In the mid-1930s, professional players in Japan were experimenting with new opening ideas. This era of Japanese go is now known as Shin Fuseki (‘New Fuseki’). In October 1934, Shinohara Masami 5-dan (Black) and Kitani Minoru 6-dan played moves 1 to 18. Could it be that they were inspired by sunjang baduk?