Go Commentary: Zen vs Franz-Josef Dickhut – 2nd Codecentric Go Challenge, Game 1

The 2nd Codecentric Go Challenge began on October 3, 2015, with the computer Go program Zen challenging 11 time German Go champion Franz-Josef Dickhut (aka FJ) in the first game of a best of five match.

The Codecentric Go Challenge

The Codecentric Go Challenge is an annual best of five match between a top computer Go program and a top amateur Go player.

The Codecentric logo.

The Codecentric logo.

The first iteration of the tournament was held in 2014 and the event is sponsored by Codecentric – an IT consulting company based in Germany.

In 2014, Dickhut defeated CrazyStone (another top Go AI) with a 3-1 score, after losing the first game.

This year, he’s facing CrazyStone’s rival, Zen.

Team DeepZen

Zen is the brainchild of two people – Yoji Ojima and Hideki Kato – who together form Team DeepZen, based in Japan.

For this match, Zen19 is using a parallelized implementation of its code, developed by Hideki. This means that it can efficiently carry out many calculations simultaneously (in parallel) when it has access to a computer cluster (multiple computers at once). This version of Zen is stronger than the commercial version when clustered.


Zen is running on a four PC cluster consisting of:

  • aย dual 12-core Xeon E5-2690 v3 at 2.6 GHz, with 32 GB RAM,
  • a dual 10-core Xeon E5-2690 v2 at 3 GHz, with 32 GB RAM,
  • a dual 6-core Xeon X5680 at 3.5 GHz, with 8 GB RAM, and
  • an 8-core Core i7 5960X at 3 GHz, with 16 GB RAM.

And Dickhut is running on a human brain ๐Ÿ˜‰

Read an interview with both teams

For more information about the match and to read an interview with both teams, please visit the Codecentric website.

Game 2 schedule

The next game will be played this weekend, on Saturday October 17, at 2:00 PM German time. That’s Saturday, 17 October at:

  • 5:00 AM US Pacific Daylight Time
  • 8:00 AM US Eastern Daylight Time
  • 12:00 PM UTC
  • 2:00 PM Central European Summer Time
  • 9:00 PM Japanese Standard Time, and
  • 11:00 PM Australian Eastern Daylight Time.

You can watch the game on the KGS Go Server (look for the game between fj and Zen19S).

More information about the match schedule is available here.

Let’s have a look at the game!

Commented game record

Zen vsย Franz-Josef Dickhut


Download SGF File (Go Game Record)


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About Younggil An

Younggil is an 8 dan professional Go player with the Korean Baduk Association. He qualified as a professional in 1997 and won an award for winning 18 consecutive professional matches the following year. After completing compulsory military service, Younggil left Korea in 2008, to teach and promote the game Go overseas. Younggil now lives in Sydney, Australia, and is one of the founders of Go Game Guru. On Friday evenings, Younggil is usually at the Sydney Go Club, where he gives weekly lessons and plays simultaneous games.

You can follow Go Game Guru on Facebook, Twitter, Google+ and Youtube.


  1. Stuart Barthropp says:

    Hi – great to see a commentary on this interesting challenge.

    Is W60 a necessary move? It looked to me like it could be a bit slow. B gains sente, and Black gets B61 and B63 which seems a big gain.

    • Younggil An says:

      Hi Stuart, that’s a good idea.

      White 60 was fine, but playing at the top or connecting at 63 instead would be also possible.

      White 60 supports his right side group, and also useful when White invade the top right corner, so that’s bigger than it looks. ๐Ÿ™‚

  2. Thank you very much for your insightful commentary on the first game of the codecentric go challenge! I have added links to your post on go.codecentric.de. I would be delighted if we can see commentaries of future rounds, too. Best regards to Australia from Germany!

  3. Thanks for the great comment, it’s really interesting to see how much emphasis Zen puts on the center.

    • Younggil An says:

      Yes, right. When I look at other strong computer programs such as Crazy Stone also emphasizes the center and they are good at it!

  4. Gil Dogon says:

    Yes, I was greatly impressed by Zens play. First of all I am a measly 1 Dan. And indeed computer go have really advanced since the early years.
    I was specially struck by B 91 and 95. I would have never thought of that line of play, and generally B “reverse scarificing” of the already captured W group in the lower left was impressive.

    Generally I feel the endgame skill of Zen is already approaching pro level, as computers can be better at counting specially towards the end …

    • Younggil An says:

      Yes, I was also surprised to see that bold sacrificing in that area, because that’s very hard for human to think about that plan.

      Zen’s endgame is generous, and it seems like it loses some points intentionally when Zen is winning by a big margin. ๐Ÿ™‚

  5. Warren Dew says:

    So, what happened in game 2?

  6. Hi Younggil,
    thanks for this interesting commentary.
    There were also two games between Rita Pocsai and Zen recently in Budapest (both available on KGS, Rita played with the account “woods”). Rita won both games, but they were hard fought. I would love to see a commentary of at least one of the games — whichever you find more interesting.

    • Younggil An says:

      Hi Mate, thanks for your kind suggestion.

      I just had a look at both games between Zen and Rita, and I felt like somehow Zen’s playing wasn’t as good as the game against Franz. Probably Rita was too strong for Zen.

      I’ll consider of that, but I was a bit disappointed by Zen’s moves in those games.

      • The reason behind Zen’s relatively worse play may have been that Rita was prepared against Zen’s center moyo strategy. It could be interesting to compare the strengths of the computer (building center moyo) and its weaknesses (fighting local fights and ko). It is good to keep in mind these weaknesses when playing against a computer ๐Ÿ™‚

        • Younggil An says:

          I see, that makes sense. Thanks Mate for your analysis.

          That’s a useful tip to keep in mind its weaknesses and strong points when playing. ๐Ÿ™‚

  7. In the end, humanity won 3-1! It would be great to see the remaining 3 games commented, even if briefly. Looking through the games, it seems that Zen died in ko, so to speak.

    • Younggil An says:

      Thanks Vladimir for the information.

      It appears that the ko is the weakest part of the computer programs.

  8. is there a version of zen for download for window PC?

    • Younggil An says:

      I have no idea, I heard a while ago that it’s not available to download, but it might have been changed.

  9. How long the time and byoyomi to play? and longer time will be advantage for which ?

    • Younggil An says:

      That’s an interesting question Matee.

      At first, I thought that human would get advantage for longer time, but I learned that computer requite more time to maintain its top strength.

      I’m not sure who has advantage for longer time, and I’m curious about that as well.