Go is a board game that is more than 2,500 years old (yes, this is not about the programming language!) and it is fascinating from multiple viewpoints. For instance, go bots still can’t beat professional players, unlike in chess. This talk will show you what is so special about Go that computers still can’t beat humans. We will take a look at the most popular underlying algorithm and show you how the Monte Carlo method, basically random simulation, plays a vital role in conquering Go's complexity and creating the strong Go bots of today.

1. 1997

2. Ing cup 1985 – 2000
(up to 1,400,000$)
(1985-2000)

3. 2001

4. 2009

5. 2014

6. 31st
October
2015

7. 3rd
November 2015

8. 13th
November 2015

9. Beating Go thanks to the power
of randomness
Tobias Pfeiffer
@PragTob
pragtob.info

47. Go vs. Chess

48. Complex vs. Complicated

49. „While the Baroque rules of chess could only
have been created by humans, the rules of
go are so elegant, organic, and rigorously
logical that if intelligent life forms exist
elsewhere in the universe, they almost
certainly play go.“
Edward Lasker (chess grandmaster)

50. Range Stage
30k-20k Beginner
19k-10k Casual Player
9k-1k Intermediate Amateur
1d-7d Advanced Amateur
1p-9p Professional

55. 5d win 1998

56. Why is Go so hard?

57. Larger board
19x19 vs. 8x8

58. Almost every move is legal

59. Average branching factor:
250 vs 35

60. State Space Complexity:
10171
vs 1047

61. 1080

62. Global impact of moves

63. Artifical Intelligence

64. 68957966354765
685766345
857635
563
6
MAX
MIN
MAX
MIN
MAX

65. 68957966354765
685766345
857635
563
6
MAX
MIN
MAX
MIN
MAX

66. 68957966354765
685766345
857635
563
6
MAX
MIN
MAX
MIN
MAX

67. 68957966354765
685766345
857635
563
6
MAX
MIN
MAX
MIN
MAX

68. 68957966354765
685766345
857635
563
6
MAX
MIN
MAX
MIN
MAX

69. Evaluation function

71. Monte Carlo Method

72. What is Pi?

73. How do you determine Pi?

75. 2006

76. Browne, Cb, and Edward Powley. 2012. A survey of monte carlo tree search methods. Intelligence and AI 4, no. 1: 1-49

77. 2/4
1/1 0/1 1/1 0/1
A1
D5
F13C7

78. 2/4
1/1 0/1 1/1 0/1
A1
D5
F13C7
Selection

79. 2/4
1/1 0/1 1/1 0/1
A1
D5
F13C7
0/0
B5
Expansion

80. 2/4
1/1 0/1 1/1 0/1
A1
D5
F13C7
0/0
B5
Simulation

82. 3/5
2/2 0/1 1/1 0/1
A1
D5
F13C7
1/1
B5
Backpropagation

83. 3/5
2/2 0/1 1/1 0/1
A1
D5
F13C7
1/1
B5
Perspective

84. 2/5
1/2 0/1 1/1 0/1
A1
D5
F13C7
1/1
B5
Perspective

85. 2/4
1/1 0/1 1/1 0/1
A1
D5
F13C7
Selection

86. Multi Armed Bandit

87. Exploitation vs Exploration

88. wins
visits
+explorationFactor
√ln(totalVisits)
visits

89. 15042
86/193
0/1 1/2 0/2
36/1116
2/2
58/151
1/2 0/23/3

90. 15042
86/193
0/1 1/2 0/2
36/1116
2/2
58/151
1/2 0/23/3

91. 15042
86/193
0/1 1/2 0/2
36/1116
2/2
58/151
1/2 0/23/3

92. Not Human like?

93. Characteristics

94. Aheuristic

95. Generate a valid random move

96. Who has won?

98. General Game Playing

99. Anytime

100. Lazy

105. -2 -1 0 1 2
8 86% 88% 90% 94% 98%
16 86% 92% 94% 94% 96%
32 94% 96% 98% 96% 95%
64 98% 99,6% 99,9% 99,4% 96%
100 99,8% 99,9% 100% 99,99% 98%

106. -2 -1 0 1 2
8 86% 88% 90% 94% 98%
16 86% 92% 94% 94% 96%
32 94% 96% 98% 96% 95%
64 98% 99,6% 99,9% 99,4% 96%
100 99,8% 99,9% 100% 99,99% 98%

107. -2 -1 0 1 2
8 86% 88% 90% 94% 98%
16 86% 92% 94% 94% 96%
32 94% 96% 98% 96% 95%
64 98% 99,6% 99,9% 99,4% 96%
100 99,8% 99,9% 100% 99,99% 98%

108. -2 -1 0 1 2
8 86% 88% 90% 94% 98%
16 86% 92% 94% 94% 96%
32 94% 96% 98% 96% 95%
64 98% 99,6% 99,9% 99,4% 96%
100 99,8% 99,9% 100% 99,99% 98%

111. Enhancements

112. All Moves As First

113. RAVE

114. Expert Knowledge

118. Selection

119. Oh yeah

120. PragTob/Rubykon

121. PragTob/web-go

122. pasky/michi

123. ujh/iomrascalai

124. What have I learned?

125. Making X faster
vs
Doing less of X

126. Modularizing small components

127. Benchmark everything

128. Solving problems the human way
vs
Solving problems the computer
way

129. Joy of Creation

130. Beating Go thanks to the power
of randomness
Tobias Pfeiffer
@PragTob
pragtob.info

131. Photo Credit
● https://en.wikipedia.org/wiki/Emperor_Yao#/media/File:Ma_Lin_-_Emperor_Yao.jpg
● https://en.wikipedia.org/wiki/Zuo_Zhuan#/media/File:Li_Yuanyang_Zuo_zhuan_first_page.png
● https://en.wikipedia.org/wiki/Four_arts#/media/File:The_Eighteen_Scholars_by_an_anonymous_Ming_artist_2.jpg
● https://en.wikipedia.org/wiki/Kibi_no_Makibi#/media/File:Kibino_Makibi.jpg
● https://en.wikipedia.org/wiki/Honinbo_Sansa#/media/File:Honinbo_Sansa.jpg
● http://www.bbc.co.uk/arts/yourpaintings/paintings/thomas-hyde-16361703-228754
● https://en.wikipedia.org/wiki/Oskar_Korschelt#/media/File:Oscar_Korschelt.jpg
● https://en.wikipedia.org/wiki/Atari#/media/File:Atari_Official_2012_Logo.svg
● http://www.computer-go.info/events/ing/2000/images/bigcup.jpg
● http://www.wired.com/2014/05/the-world-of-computer-go/
● https://en.wikipedia.org/wiki/File:Radha-Krishna_chess.jpg
● https://en.wikipedia.org/wiki/File:EnxadrismoGravuras.003.jpg
● http://archive.is/QG6a
● http://giphy.com/gifs/monkey-bubbles-chimp-2Faz9OUQfOcltIJTG
● https://en.wikipedia.org/wiki/The_Turk#/media/File:Turk-engraving5.jpg
● https://en.wikipedia.org/wiki/File:Kasparov-29.jpg
● CC BY 2.0
– https://en.wikipedia.org/wiki/File:Deep_Blue.jpg
–
● CC BY-SA 3.0
– https://en.wikipedia.org/wiki/Konrad_Zuse#/media/File:Konrad_Zuse_%281992%29.jpg
– https://en.wikipedia.org/wiki/Alpha%E2%80%93beta_pruning#/media/File:AB_pruning.svg
– https://en.wikipedia.org/wiki/Go_%28programming_language%29#/media/File:Golang.png

132. Photo Credit
● https://en.wikipedia.org/wiki/Emperor_Yao#/media/File:Ma_Lin_-_Emperor_Yao.jpg
● https://en.wikipedia.org/wiki/Atari#/media/File:Atari_Official_2012_Logo.svg
● http://www.computer-go.info/events/ing/2000/images/bigcup.jpg
● http://www.wired.com/2014/05/the-world-of-computer-go/
● http://archive.is/QG6a
● https://en.wikipedia.org/wiki/The_Turk#/media/File:Turk-engraving5.jpg
●
https://en.wikipedia.org/wiki/File:Kasparov-29.jpg
● CC BY 2.0
– https://en.wikipedia.org/wiki/File:Deep_Blue.jpg
–
● CC BY-SA 3.0
– https://en.wikipedia.org/wiki/Konrad_Zuse#/media/File:Konrad_Zuse_%281992%29.jpg
– https://en.wikipedia.org/wiki/Alpha%E2%80%93beta_pruning#/media/File:AB_pruning.svg
– https://en.wikipedia.org/wiki/Go_%28programming_language%29#/media/File:Golang.png
● CC BY-SA 2.0
– https://www.flickr.com/photos/mike_miley/7762037662/in/photolist-cPUtny-2Jyv1K-6rkH7Y-pDdKnE-6W7Amw-
pDYyb5-pVK2bG-5cavw1-jbNWJC-6rgxSr-cKt4c-5w7uns-pDbh7H-4swKk-9TAvoC-nMY3Do-51yJaD-eUrQ5d-mHs87x-nEkW
87-hmMnyg-o3Enjw-rf7AY5-8hAiN6-eY3iqs-9fmGiN-sSzYQ-oq6rm2-oA9xdT-froGke-gJ8cJ8-igt2FS-mRz9Gc-gMexAK-
eSKEzV-nPy1Zu-527E2U-pEgLhp-ivCWw8-bpCbU-qb22fr-odobP9-htytWv-k4NMKa-dCNpPk-foM8Lk-o73rga-dNvVbs-na2
qUc-eXLwhK

133. Photo Credit
● https://en.wikipedia.org/wiki/Emperor_Yao#/media/File:Ma_Lin_-_Emperor_Yao.jpg
● https://en.wikipedia.org/wiki/Zuo_Zhuan#/media/File:Li_Yuanyang_Zuo_zhuan_first_page.png
● https://en.wikipedia.org/wiki/Four_arts#/media/File:The_Eighteen_Scholars_by_an_anonymous_Ming_artist_2.jpg
● https://en.wikipedia.org/wiki/Kibi_no_Makibi#/media/File:Kibino_Makibi.jpg
● https://en.wikipedia.org/wiki/Honinbo_Sansa#/media/File:Honinbo_Sansa.jpg
● http://www.bbc.co.uk/arts/yourpaintings/paintings/thomas-hyde-16361703-228754
● https://en.wikipedia.org/wiki/Oskar_Korschelt#/media/File:Oscar_Korschelt.jpg
● https://en.wikipedia.org/wiki/Atari#/media/File:Atari_Official_2012_Logo.svg
● http://www.computer-go.info/events/ing/2000/images/bigcup.jpg
● http://www.wired.com/2014/05/the-world-of-computer-go/
● https://en.wikipedia.org/wiki/File:Radha-Krishna_chess.jpg
● https://en.wikipedia.org/wiki/File:EnxadrismoGravuras.003.jpg
● http://archive.is/QG6a
● http://giphy.com/gifs/monkey-bubbles-chimp-2Faz9OUQfOcltIJTG
● https://en.wikipedia.org/wiki/The_Turk#/media/File:Turk-engraving5.jpg
● https://en.wikipedia.org/wiki/File:Kasparov-29.jpg
● CC BY 2.0
– https://en.wikipedia.org/wiki/File:Deep_Blue.jpg
–
● CC BY-SA 3.0
– https://en.wikipedia.org/wiki/Konrad_Zuse#/media/File:Konrad_Zuse_%281992%29.jpg
– https://en.wikipedia.org/wiki/Alpha%E2%80%93beta_pruning#/media/File:AB_pruning.svg
– https://en.wikipedia.org/wiki/Go_%28programming_language%29#/media/File:Golang.png

134. Photo Credit
● https://en.wikipedia.org/wiki/Emperor_Yao#/media/File:Ma_Lin_-_Emperor_Yao.jpg
● https://en.wikipedia.org/wiki/Zuo_Zhuan#/media/File:Li_Yuanyang_Zuo_zhuan_first_page.png
● https://en.wikipedia.org/wiki/Four_arts#/media/File:The_Eighteen_Scholars_by_an_anonymous_Ming_artist_2.jpg
● https://en.wikipedia.org/wiki/Kibi_no_Makibi#/media/File:Kibino_Makibi.jpg
● https://en.wikipedia.org/wiki/Honinbo_Sansa#/media/File:Honinbo_Sansa.jpg
● http://www.bbc.co.uk/arts/yourpaintings/paintings/thomas-hyde-16361703-228754
● https://en.wikipedia.org/wiki/Oskar_Korschelt#/media/File:Oscar_Korschelt.jpg
● https://en.wikipedia.org/wiki/Atari#/media/File:Atari_Official_2012_Logo.svg
● http://www.computer-go.info/events/ing/2000/images/bigcup.jpg
● http://www.wired.com/2014/05/the-world-of-computer-go/
● https://en.wikipedia.org/wiki/File:Radha-Krishna_chess.jpg
● https://en.wikipedia.org/wiki/File:EnxadrismoGravuras.003.jpg
● http://archive.is/QG6a
● http://www.usgo.org/news/2011/07/hikaru-anime-on-hulu-and-netflix/
● https://en.wikipedia.org/wiki/The_Turk#/media/File:Turk-engraving5.jpg
● https://en.wikipedia.org/wiki/File:Kasparov-29.jpg
● CC BY 2.0
– https://en.wikipedia.org/wiki/File:Deep_Blue.jpg
– https://www.flickr.com/photos/aigle_dore/14110664878/in/photolist-nuUR4u-e1q7YM-5Mqchf-rMcnKt-6rF4Td-aiMGos-nVks3G-7eKpi2-4iRRUa-ecdN2m-t33akk-8
CQwoX-firCja-8TAfbC-5Do92i-4U6yXA-dQUgdC-2hkKMK-cMgbim-iniaf-7xxKyM-eqqmuT-a7WHU1-5ZbrEE-g97Nph-35ASJL-gJtoKD-9TDrt-fz3bSd-4qAGhJ-ge5BS1-bxiUwu-
6wYoR8-5UbciZ-84AZHc-59efoV-8gZ1yt-9Le6DZ-dy74yw-pWJVFe-2xCwen-omzMF4-nGgBMj-rq82wx-4GrWvo-yPvGeK-6NuTMt-9eGoR4-9ZifBq-db2fLW
● CC BY-SA 3.0
– https://en.wikipedia.org/wiki/Konrad_Zuse#/media/File:Konrad_Zuse_%281992%29.jpg
– https://en.wikipedia.org/wiki/Alpha%E2%80%93beta_pruning#/media/File:AB_pruning.svg
– https://en.wikipedia.org/wiki/Go_%28programming_language%29#/media/File:Golang.png

135. Photo Credit
● CC BY-NC-ND 2.0
– https://www.flickr.com/photos/aerialcamera/15753422176/in/photolist-q15pzb-5o8noQ-9kzjxL-2j8Cjg
-e5yjMU-7xTuVB-n75WB6-dCg74N-71JXoJ-8NwBqb-j3typA-79oGNv-aEvcKT-r9j7s2-6pSzwn-aURgGr-j69RDV-4Tw
VKe-6dGZqk-6FjmMs-8kWfPL-jJMnA2-aA4SnC-7rCdVT-92CTsh-9vbC6n-92CTME-7bhyei-92zK8B-qzprcx-7yhuE8-
gmpP3A-gmq6uT-9m5Gyx-9m5F9B-2G7F7A-o9fpEY-q2uByi-92DKJr-7T8jPc-92qCsX-acbDAF-7QutRi-cZLZLU-azER
ev-a3Lcnj-gmoQYw-93s1fE-noZEfj-6jrkdA
– https://www.flickr.com/photos/stargardener/7037360553/in/photolist-bHSj7D-ipFVRk-dbQMMF-9pkdk1-
akZXq-ocP2RE-6Rog8i-4NZtZG-aM7Tr4-83N9cr-avkRuq-wUzMF-xvV8G-6EoNDC-bqG35H-8tZTNm-bit9C-xiQv5-7p
W2xg-5z58z8-wtDY8-bA2bvb-duBtzt-9hnK36-pTKW9S-6GEZSe-9KaFui-9ZAgm1-djUsDh-oPTkQ4-7wwnMo-4wSaYW-
JyEqK-4tZTqD-9cdenf-na9Bzc-pwiEWL-9ipZiR-prY2Z1-pyTq4i-6Qq3bR-bjFP7x-bXCB3s-77WG8U-pbnQ5v-avy5c
r-3YdbZj-4wuUvu-qs91kS-dg6cjy
– https://www.flickr.com/photos/andreastsonis/11518720353/in/photolist-ixSsfM-iFE9j2-8R7Now-cXNz
15-9iL3iz-iw1VTu-9GvRkV-egTDcw-9iK9Nx-9CpqPB-oDZVWG-egMSC6-egMT2r-egMTez-r54iiS-egMSjr-egMR4Z-
egTAMQ-egTCfj-egTFt3-egTCrs-egMTWc-egM1Nx-eeDtNx-9iKvwP-9iLhCp-9iPgrL-egTE8J-egTERq-egTDU5-egM
Rpv-egTC5u-egTBXf-egTBEC-egTFg3-egTF5h-egMUca-egMQRF-egaYGL-9BRUZh-efDsaf-9B7mJK-efDtPh-9BNXsk
-9Ctoyf-egN3dk-9BaGPu-9iLfpZ-9GvRFM-9GyJR7
–
● https://en.wikipedia.org/wiki/Alphabet_Inc.#/media/File:Alphabet_Inc_Logo_2015.svg
● CC BY-NC 2.0
– https://www.flickr.com/photos/sutekidane/2199385255/in/photolist-4mmqBr-7NqSe4-abChUK-9NA6gV-
755hWp-q4tjgW-8FCyzU-4zcMni-abESMd-4hMNYF-6c24D1-tBRRPr-qDt6Bt-4hRU9J-sEKsZd-a2x9tv-ampYHm-7m
2UsB-abDDQy-tkiVfc-pJr2of-4t4uQA-enwU-3d2tQV-d8cmaf-4Ymd6d-enwJ-huAHMi-gE97EH-zFu7N-otJ1TR-4V
AkNv-utVH9-tkak53-56vGR-6LbDW8-c4R6PN-3Hn7Le-abEBUA-7JMTVd-7XodLF-eb2Sme-77gM4Z-6WxHh8-oLcvhR
-9NA4Yk-4YgWen-oLctgr-otH1Dd-oLcrXe
–
● CC BY 3.0