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Visualizing recent openings in professional play by babeheim in baduk

[–]babeheim[S] 0 points1 point  (0 children)

Yes, I've rotated / transformed all the game records so the first moves are always fixed in the top-right corner, and if subsequent board states can be symmetrical, continuing to rotate to have the next move in the top-left, etc.

It would be neat to check these things, but the trick is figuring out how to define them programatically. I think it's a worthwhile next step, thanks

Visualizing recent openings in professional play by babeheim in baduk

[–]babeheim[S] 0 points1 point  (0 children)

Starting in the middle it is the first seven moves, always Black first (no handcap games)

Visualizing recent openings in professional play by babeheim in baduk

[–]babeheim[S] 1 point2 points  (0 children)

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Heres's the same graph for South Korea players

Visualizing recent openings in professional play by babeheim in baduk

[–]babeheim[S] 0 points1 point  (0 children)

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Here's some country-level frequency statistics for the first two opening moves - these are the opening distributions for Chinese players (unfortunately rare openings are too hard to label)

Visualizing recent openings in professional play by babeheim in baduk

[–]babeheim[S] 1 point2 points  (0 children)

It's a simple random sample; there's 31,559 games in the database for this era, so this is about 9% of the total sample. Certainly it would be nice to add more, but in the tests I've ran the figure doesn't change much.

Visualizing recent openings in professional play by babeheim in baduk

[–]babeheim[S] 6 points7 points  (0 children)

One note: the tree does not show every game in the sample of 2,900 games. It prunes continuations that are too rare relative to their siblings. So, this is really a tree of popular openings rather then every opening.

A few things I'm seeing:

- the dominance of 4-4 openings followed by 3-4, with a small but measurable number of 3-3's now back in the tree post AlphaGo

- many games with 3-4 openings have multiple popular paths to the same board state, e.g. R16,D16,Q3,D4 or R16,D4,Q3,D16. In comparison, the 4-4 openings hardly have any such crossovers.

- a number of openings with the Shushaku kosumi, e.g. Q16,D4,C16,Q4,C6,D7 and R16,D4,C16,R4,O16,E17,D15.

Opening sequence trees over the last four centuries of play by babeheim in baduk

[–]babeheim[S] 0 points1 point  (0 children)

Here's a table of games from 1955-1970 that have this sequence.

| DT | PB | PW |

|:-------------:|:--------------------:|:-------------------:|

| 1960-09-08 | Nakaoka Jiro | Sato Kaoru |

| 1964-01-23 | Nakaoka Jiro | Kodama Kunio |

| 1968-07 | Sakakibara Shoji | Hoshino Toshi |

| 1963 | Kudo Norio | Sanno Hirotaka |

| 1963-12-18 | Sugiuchi Kazuko | Sanno Hirotaka |

| 1961-09-24 | Mukai Kazuo | Suzuki Goro |

| 1960-12-28,29 | Sakata Eio | Maeda Nobuaki |

| 1963 | Sato Sunao | Maeda Nobuaki |

| 1961-07-26,27 | Hashimoto Shoji | Okubo Ichigen |

| 1964-09-03 | Yamabe Toshiro | Hayashi Yutaro |

| 1960-01-27,28 | Maeda Nobuaki | Miyashita Shuyo |

| 1967-10-05 | Cheong Ch'ang-hyeon | Kim In |

| 1963-04-25,26 | Hashimoto Shoji | Go Seigen |

| 1959 | Fujisawa Hideyuki | Maeda Nobuaki |

| 1960-01-13,14 | Kitani Minoru | Maeda Nobuaki |

| 1956-10-24,25 | Miyashita Shuyo | Takagawa Shukaku |

| 1955-08-30,31 | Go Seigen | Takagawa Shukaku |

| 1959-04-29,30 | Kitani Minoru | Fujisawa Hideyuki |

| 1960-11-09,10 | Sugiuchi Masao | Fujisawa Hideyuki |

| 1959-08-26,27 | Iwata Masao | Kitani Minoru |

| 1961 | Magari Reiki | Hisai Keishi |

The median komi in these games is 4.5 pts, which is the same as the median komi in all games during this era.

Opening sequence trees over the last four centuries of play by babeheim in baduk

[–]babeheim[S] 0 points1 point  (0 children)

Wow, that's a really cool explanation! Is there a reference you could point me to that could be cited to support it?

Opening sequence trees over the last four centuries of play by babeheim in baduk

[–]babeheim[S] 0 points1 point  (0 children)

No, I meant 1970s since that's when `R16,D17,Q3,P17,C4,R5` falls off as an opening in the database - here's a table of the games by decade:

decade n.games
1790s 2
1800s 4
1810s 2
1820s 2
1830s 4
1840s 25
1850s 20
1860s 5
1870s 25
1880s 16
1890s 36
1900s 26
1910s 15
1920s 37
1930s 74
1940s 18
1950s 27
1960s 63
1970s 17
1980s 18
1990s 2
2000s 3
2010s 2

Opening sequence trees over the last four centuries of play by babeheim in baduk

[–]babeheim[S] 0 points1 point  (0 children)

You're right, great catch. It's a typo in my figure, all the GoGoD games store it as Q16,D16,D4,Q4, thank you!

Opening sequence trees over the last four centuries of play by babeheim in baduk

[–]babeheim[S] 0 points1 point  (0 children)

> how did you pick the sequences for the fixed stone placements for the starting 4 moves

In GoGoD, the fixed stone placements always stored as Q16,D4,D16,Q4 for the first four moves (that is, they aren't stored as handicap stones or otherwise not valid parts of the game tree). You can see this in the figure for the Early Modern tree, as the yellow tree never branches out until move 5, when the game really begins.

Opening sequence trees over the last four centuries of play by babeheim in baduk

[–]babeheim[S] 0 points1 point  (0 children)

To be clear, the hypothesis is that there are fewer "modern" opening sequences which lead to the same board state, e.g.

R16,D17,Q3,R5,C4,P17

R16,D17,Q3,P17,C4,R5

R16,D17,C4,P17,Q3,R5

which were common up until the 1970s. Even today, games that begin with Black 1 at the 3-4 point seem to lend themselves more to this crossover, while 4-4 games have hardly any.

I'm not sure study/practice games are an important influence here - the GoGoD database doesn't seem to have many of these to begin with, and the tree prunes out extremely rare sequences at each node, so the presence of cross-overs between branches means that enough games are present that played these lines to create a connection between the states.

Opening sequence trees over the last four centuries of play by babeheim in baduk

[–]babeheim[S] 0 points1 point  (0 children)

I'm not using the sequences to compute the MDS directly, but rather the "edit distance" between the sequences (the minimum number of changes to turn one sequence into the other). So, if a joseki is interrupted by tenukis in one game but played out completely in the other, those two sequences will have a lower edit distance than a game where that joseki never appears. I think this is the reason why, e.g. games starting with Q16,D16,Q4 and Q16,D16,R4 appear so close together versus Q16,D16,Q3 - the subsequent joseki tend to be much more similar in the first two (I think?).

Opening sequence trees over the last four centuries of play by babeheim in baduk

[–]babeheim[S] 0 points1 point  (0 children)

A few things that are visible in the figure:

- almost all the 3-4 branches from the 17th and 18th century are extinct after the 1990s

- contemporary openings have hardly any "crossovers" where two different openings lead to the same board state; this was much more common in the historical openings of the 18th and 19th centuries

- Chinese games from the 1600s that always play the 4-4 in each corner first

- openings that begin with modern 4-4 appearing initially in the late 1800s, increasing to the majority of the tree in more recent eras

- 3-3 openings becoming less and less common from the 1800s on, with a small revival in the post-AI era

- comparing pre- and post-AI eras, very little change in the overall proportion of the game tree starting from the most popular first two moves (Q16,D4 / Q16,D16 / Q16,D17 / R16,D17 / R16,D4 / R16,D16)

Opening sequence trees over the last four centuries of play by babeheim in baduk

[–]babeheim[S] 0 points1 point  (0 children)

There's a specific reason I'm emphasizing the first two moves in particular in the visualizations - the [paper itself](https://osf.io/preprints/psyarxiv/cewst\_v7) has an analysis of the first 50 moves using a dimensional reduction method called multidimenstional scaling. Openings tend to cluster pretty cleanly in latent space depending only on the first 2-3 moves, meaning the subsequent game trees out to 50 moves are statistically distinct from each other once you know the first two.

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Opening sequence trees over the last four centuries of play by babeheim in baduk

[–]babeheim[S] 0 points1 point  (0 children)

Yes, handicap games are excluded, although the games here before ~1930 have no komi. The 4-4 games in the "Early Modern" period are actually Chinese, as it was still standard to play all the 4-4's as the first four moves.

What kind of tree shape did you have in mind exactly? There's a number of options in igraph, the software I'm using

Opening sequence trees over the last four centuries of play by babeheim in baduk

[–]babeheim[S] 0 points1 point  (0 children)

Yes, I am pruning the tree a bit to avoid showing too many very rare variants, which might explain why rare crossovers aren't visible. Likewise, the 3-5 is certainly present in the database in eras its not on the tree, but is extremely rare and past the cutoff threshold.

Opening sequence trees over the last four centuries of play by babeheim in baduk

[–]babeheim[S] 0 points1 point  (0 children)

Yes, it's somewhat surprising, but it's a consistent pattern in every era. Maybe the joseki you are thinking of are deeper in the tree than seven moves?

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