Showing posts with label go. Show all posts
Showing posts with label go. Show all posts

Dec 18, 2025

NoGo

NoGo is a 2005 game by John Moore.

This is a game using the concepts and rules of Go, with some simplifications.

Rules:

  • On her turn, the player drops a friendly piece on an empty intersection such that all existing groups of pieces (of either color) have, at least, one liberty (so, no captures or suicides are allowed)
  • Wins the last player to move

Black moved last; there is no valid drop left,
so Black wins the match

This is a game that can be analyzed by the tools of Combinatorial Game Theory. The game can be split in a sum of games, when parts of the board no longer interact. For example, using a one-dimensional NoGo, the game o..xxo..xx can be split and simplified by two (in this case equal) subgames: o..x and o..x; this type of property is crucial to computing large game positions.

Moore initially called the game Anti-Atari Go at Sensei's Library. The name No Go meant, back then, another different go variant: After a player has made a move, his opponent may refuse it, and he must make another one. The opponent may not object to this second move (this variant is now known as Forced Takeback Go at Sensei's Library).

There's a ZRF and a Ludii to play the game.

Jul 27, 2025

Rosette

Rosette is a 1975 game by Mark Berger, published at Games & Puzzles #34:

Mindsports has more information about this early Go variant. Also check this BGG forum discussion.

Mar 24, 2007

Area vs Territory Go Rules

[Bill Taylor] The following Go example shows a safe set of stones with two eyes:

. . . . . .
. . o o . .
. o o . o .
. o . o o .
. . o o . .
. . . . . .


Would this set be called a single group even though it is composed of two disconnected halves?

Most players would call it a single group. In area rules it doesn't matter what you call it. In territory rules it could conceivably matter what you call it, (though it doesn't in practice), because territory rules, in all their artificial absurdity, have to refer to groups from time to time in order to define what is considered "dead" and what is considered "alive".

In territory rules, this matters(!). In area rules, it doesn't matter - if there is any dispute you just play it out (and with no cost) until a group or groups is removed from the board.

Logically speaking, you should call the above two separate groups, each helping to keep the other alive. But people never speak so precisely in practice.

There is even a worse situation. The following group has only one true "eye"; the other one, in the NW corner, is a so-called "false eye", and can eventually be filled and the whole lot captured.

. x x . o .
x o o o o o
x x x x o .
x . x x o o
x x x x o .


Territory rules actually have to define the concept of eyes, false eyes, and the rest. It is lunacy. (Area rules define nothing - you just play it out to the grim end if necessary). Territory rules, with their defined false eyes, come to grief in this famous sort of position:

. x x x x x | Here, black has TWO false eyes, and not a single true one!
x o o o o x | And yet, both separate groups, or parts of a group, are
x o o . o x | keeping one another alive; rather like your above example.
x o . o o x |
x o o o o x | And even the Japanese admit that black is alive, in spite of
x x x x x . | what their rule books say!

Basically, territory rules are an abortion. Computers cannot handle them because they are essentially logically flawed.

Mar 23, 2007

Go and the 'Three Games'

Go and the 'Three Games' -- A text by William Pinckard

Games-playing is one of the oldest and most enduring human traits. Disparate pieces of evidence such as dice discovered at Sumer, game-boards depicted on Egyptian frescoes, Viking chess pieces, and ball parks constructed by ancient empires deep in the Andes link up directly with contemporary phenomena such as Saturday night poker games in Kansas City and the annual go title matches in Tokyo.

Games are undeniably a concomitant of civilization and even in their most primitive forms presuppose some degree of sophistication. Most of all, they require the ability to think in abstractions and to manipulate ideas in logical terms, thereby giving form to what is formless and creating small, recognizable patterns in the shadow of great mysteries.

From ancient times in Japan the so-called 'Three Games' were backgammon, chess and go. Chess probably comes from India, backgammon from the Near or Middle East, and go from pre-Han China. Backgammon is a gambling game which, using dice, gives luck or chance the preponderant role. Chess in one of its earlier forms also used dice, but takes its present shape from the structure of a royal society and from war maneuvers. Go is the most abstract and 'open' of the three; and with its freedom from complicated rules, its simplicity of form, its fluidity and spaciousness, it comes remarkably close to being an ideal mirror for reflecting basic processes of mentation.

Go is played with black and white 'stones' all of exactly the same value, thus somewhat resembling the binary mathematics which is the basis of the computer. The stones are played onto the board and are left as they stand throughout the game, so that the game itself takes shape as a visible record of the thinking that went into it. About three hundred years ago an eminent Chinese monk came to Japan on a visit and was shown the diagram of a game of go which a master of that time had recently played. Without knowing anything of the game save the sketchy description they gave him at the time (this was after go had more or less died out in China), the monk studied the moves as shown on the record and after a few moments remarked with much admiration and respect that the player must have been a man who had become enlightened -- which was indeed the case. (It is interesting to note that this story is told on the one hand by go players to illustrate the quality of the game and on the other hand by Buddhists to show the acuity of the monk from China.)

The great 17th century Japanese playwright Chikamatsu, in a famous passage, compares the four quarters of the go board to the four seasons, the black and white stones to night and day, the 361 intersections of the board to the days of the year, and the center point on the board to the Pole Star. It would be easy to erect a tower of fanciful theory along these lines, but that would only obscure the obvious point. In this striking analogy Chikamatsu is describing a feeling of hugeness and all-inclusiveness -- the board conceived as a complete world system in potential form. The board and pieces can be thought of as limitless: any number of lines and an endless supply of stones to play with, the game itself being the life of the players. (In Chikamatsu's play a young man becomes old and grows a long beard while watching a single game.) Only because we are human and must put practical limits to our activities, do we use just a small part of the infinite board. But this field of nineteen by nineteen is large enough to contain everything we are able to put into it. The number of possible games playable on this board has been reckoned to be more than the number of molecules in the universe.

An anonymous go player has written: 'The board is a mirror of the mind of the player as the moments pass. When a master studies the record of a game he can tell at what point greed overtook the pupil, when he became tired, when he fell into stupidity, and when the maid came by with the tea.'

Contrary to the opinion of many people, go has nothing to do with Buddhism. Because it is a valid system in itself, it offers nothing contradictory to other systems, but in fact go is an older inhabitant on this planet than is Buddhism. In China it became one of the Four Accomplishments, the others being poetry, painting and music. It reached Japan around the 6th century and for a long time remained the exclusive property of a leisured noble class. Then during the 16th century all this changed. The many great families and clans which had warred happily against each other for a thousand years were gradually brought under the hegemony of the Tokugawa Shogunate. It was during the subsequent period of the Tokugawa era (roughly from 1600 to 1868) that go, along with haiku, kendo, tea ceremony and so on, was most actively cultivated as a way of constructively channeling the mental energies of the people during the long years of peace. One formal word for go in Japanese is Kido. Ki is the old Chinese word for go, and -do is the Chinese word for Tao, which means Way -- or, more specifically, a Way to enlightenment.

All games channel mental energies, whether they lead to enlightenment or the reverse, but it is suggestive to consider the 'Three Games' in their social context because then we can see how each of them reflects certain basic characteristics of a general or regional type.

Chess, for example, the great historical game of the West, involves monarchs, armies, slaughter, and the eventual destruction of one king by another. The game appears to be entirely directed along the lines of the great myths of the West from the Mahabharata to the Song of Roland -- the overthrow of a hero and the crowning of a new hero. The pieces, from king down to pawn (peon), give a picture of a heirarchical and pyramidal society with powers strictly defined and limited.

Backgammon, the favorite game of the Near and Middle East, is preoccupied with the question of Chance and Fate (Kismet). All play is governed by the roll of dice over which the player has no control whatever. The players are matched against each other, but each tries to capture a wave of luck and ride it to victory. The loser curses his misfortune and tries again, but the individual is helpless in the grip of superior forces.

Go, the game of ancient China and modern Japan (and now popular throughout the world), is unique in that every piece is of equal value and can be played anywhere on the board. The aim is not to destroy but to build territory. Single stones become groups, and groups become organic structures which live or die. A stone's power depends on its location and the moment. Over the entire board there occur transformations of growth and decay, movement and stasis, small defeats and temporary victories. The stronger player is the teacher, the weaker is the learner, and even today the polite way to ask for a game is to say 'Please teach me.'

Things are different now, but in earlier times, when go was so much admired by painters and poets, generals and monks, the point of the game was not so much for one player to overcome another but for both to engage in a kind of cooperative dialogue ('hand conversation', they used to call it) with the aim of overcoming a common enemy. The common enemy was, of course, as it always is, human weaknesses: greed, anger and stupidity.

Every year in March department stores all over Japan present elaborate displays in connection with the Doll Festival. If one looks carefully at the miniature weapons, musical instruments and furniture of a really complete display one will find a tiny backgammon board, a Japanese chess (shogi) board and a go board.

The 'Three Games' is a useful classification because taken together they make up a coherent world view. Most of philosophy boils down to speculation centered around the three basic relationships of the human species. The first is man in his relationship to the remote gods and the mysterious forces of the universe. The second is man in the society he builds up around him. The third is man in his own self. Or, to put it another way, man the backgammon-player, man the chess-player, and man the go-player.

That we have these three shows that they answer basic needs in the human spirit. People everywhere are preoccupied with social structures, position and status; and everyone who is capable of reflection must sometimes speculate on his private relationship to fortune and fate.

But go is the one game which turns all preoccupations and speculations back on their source. It says, in effect, that everyone starts out equal, that everyone begins with an empty board and with no limitations, and that what happens thereafter is not fate or wealth or social position but only the quality of your own mind.

RingGo 80% Go 20% Hex

[(C) 2001 William I. Chang] RingGo is a variant of Go played on a hexagonal lattice with 127 points, 18 of which are removed from play in order to strike a balance between how easy or hard it is to make a group of stones live. The board inherits from Rosette, Medusa, and especially a conversation with Greg Van Patten. Most points have 4 liberties.  While it is harder to make two eyes, it is easier to connect groups so the network may have two eyes.  In this sense, I think the game achieves its goal of combining Go's intricate eye-making tactical play with the connection-making strategy of Hex (though perhaps not enough of the latter).  I'm sure it can be refined and improved if more people tried it.  The board is generalizable to odd-order lattices by repeating the Medusa pattern, although there are lots of other beautiful patterns to choose from.

           . . . . . . .                  . . . . . . . . .
          . . . . . . . .                . . . . . . . . . .
         . . . o . o . . .              . . . o . o . o . . .
        . . o . . . . o . .            . . o . . . . . . o . .
       . . . . . o . . . . .          . . . . . o . o . . . . .
      . . o . o . . o . o . .        . . o . o . . . . o . o . .
     . . . . . . . . . . . . .      . . . . . . . o . . . . . . .
      . . o . o . . o . o . .      . . o . o . o . . o . o . o . .
       . . . . . o . . . . .      . . . . . . . . . . . . . . . . .
        . . o . . . . o . .        . . o . o . o . . o . o . o . .
         . . . o . o . . .          . . . . . . . o . . . . . . .
          . . . . . . . .            . . o . o . . . . o . o . .
           . . . . . . .              . . . . . o . o . . . . .
                                       . . o . . . . . . o . .
             . . . . .                  . . . o . o . o . . .
            . . . . . .                  . . . . . . . . . .
           . . . o . . .                  . . . . . . . . .
          . . o . . o . .
         . . . . . . . . .
          . . o . . o . .     RingGo boards of order 5/7/9, with 55/109/193
           . . . o . . .      points.  The order-11 board has 301 points.
            . . . . . .
             . . . . .


One might play RingGo on a Go board if one can envision dividing each
square into two triangles with a diagonal line drawn top-left/bottom-right.
(There actually was a commercial version of Hex done this way!)  Or, have
the players sit adjacent and both look toward the *.

   . . . . . . .           *
   . . . . . . . .
   . . . o . o . . .
   . . o . . . . o . .
   . . . . . o . . . . .
   . . o . o . . o . o . .
W   . . . . . . . . . . . . .
     . . o . o . . o . o . .
       . . . . . o . . . . .
         . . o . . . . o . .
           . . . o . o . . .
             . . . . . . . .
               . . . . . . .

               B


This game should play very differently from other hexagonal Go variants.
I tried and liked it :-)  Any suggestions or comments will be greatly
appreciated!

William Chang   Los Gatos, California   18 April 2001
email: wchang@acm.org, williamichang@hotmail.com
(C) 2001 William I. Chang

---

Other Boards:

Rings board

          o o   o o   o o
         o   o o   o o   o
          o o   o o   o o
       o o   o o   o o   o o
      o   o o   o o   o o   o
       o o   o o   o o   o o
    o o   o o   o o   o o   o o
   o   o o   o o   o o   o o   o
    o o   o o   o o   o o   o o
       o o   o o   o o   o o
      o   o o   o o   o o   o
       o o   o o   o o   o o
          o o   o o   o o
         o   o o   o o   o
          o o   o o   o o

Medusa board

          o o o o o o o o
         o   o   o   o   o
        o o o o o o o o o o
       o   o   o   o   o   o
      o o o o o o o o o o o o
     o   o   o   o   o   o   o
    o o o o o o o o o o o o o o
   o   o   o   o   o   o   o   o
    o o o o o o o o o o o o o o
     o   o   o   o   o   o   o
      o o o o o o o o o o o o
       o   o   o   o   o   o
        o o o o o o o o o o
         o   o   o   o   o
          o o o o o o o o

Feb 8, 2007

A new way to play computer-Go?

Computers have started to outperform humans in games they used to lose [full text here]


[...] Deep Blue and its successors beat Mr Kasparov using the “brute force” technique. Rather than search for the best move in a given position, as humans do, the computer considers all white's moves—even bad ones—and all black's possible replies, and all white's replies to those replies, and so on for, say, a dozen turns. The resulting map of possible moves has millions of branches. The computer combs through the possible outcomes and plays the one move that would give its opponent the fewest chances of winning.

Unfortunately, brute force will not work in Go. First, the game has many more possible positions than chess does. Second, the number of possible moves from a typical position in Go is about 200, compared with about a dozen in chess. Finally, evaluating a Go position is fiendishly difficult. The fastest programs can assess just 50 positions a second, compared with 500,000 in chess. Clearly, some sort of finesse is required.

In the past two decades researchers have explored several alternative strategies, from neural networks to general rules based on advice from expert players, with indifferent results. Now, however, programmers are making impressive gains with a technique known as the Monte Carlo method. This form of statistical sampling is hardly new: it was originally developed in the Manhattan project to build the first nuclear bombs in the 1940s. But it is proving effective. Given a position, a program using a Monte Carlo algorithm contemplates every move and plays a large number of random games to see what happens. If it wins in 80% of those games, the move is probably good. Otherwise, it keeps looking.

This may sound like a lot of effort but generating random games is the sort of thing computers excel at. In fact, Monte Carlo techniques are much faster than brute force. Moreover, two Hungarian computer scientists have recently added an elegant twist that allows the algorithm to focus on the most promising moves without sacrificing speed.

The result is a new generation of fast programs that play particularly well on small versions of the Go board. In the past few months Monte Carlo-based programs have dominated computer tournaments on nine- and 13-line grids. MoGo, a program developed by researchers from the University of Paris, has even beaten a couple of strong human players on the smaller of these boards—unthinkable a year ago. It is ranked 2,323rd in the world and in Europe's top 300. Although MoGo is still some way from competing on the full-size Go grid, humanity may ultimately have to accept defeat on yet another front.

Copyright © 2007 The Economist Newspaper and The Economist Group. All rights reserved.

Oct 26, 2006

SLOW PROGRESSIVE GO 9x9

This game uses a progressive mutator in order to increase the dynamics of the original game. However, unrestricted Go drops would kill the game so two restrictions are added: (a) each stone on a drop sequence cannot belong to the same group (b) an atari stops the sequence.

Here's an example at a 9x9 board (white won 41-40). Herein it is used the slow progressive (1222344456667...)

a b c d e f g h i
. . . o x . . . . 1: c7
. . . o x . . . . 2: g3 g6
. . o o x . x x . 3: c3 e8
. . o x . . . . . 4: e2 g8
. . . o x . . . . 5: d2 d5 e7
. . . . o x x . . 6: d4 e3 e5 f7
. . o . o x . . . 7: d1 c4 e6 f9
. . . . o o x . . 8: e1 f6 g9 h3
. . . . . o x . . 9: d3 f8
a b c d e f g h i

Jan 28, 2005

Still about a little Go change

[check previous] What should happen around the edges? Should pushes be allowed? The rule can be restated as: "If an isolated piece is in atari, the other player may push it into that empty cell."

This means that the next move would be possible:

  . . . .       . . . .
  . x o .       . x o .
  x . x o       x x o <
  [edge]        [edge]

This rule still has the effect of eventually create new eyes and more KO problems. One way to solve that is to state the rule like this: "If an isolated piece is in atari, the other player may push it into that empty cell, placing a new stone on that cell".

The previous move would result on the next position:

  . . . . .
  . x o .
  x x o o
  [edge]

Nov 16, 2004

Little Go change

I found many reflexes of Go on my voyages. One of those were a game with the same rules of our Go but with a different fix for KO positions. They had an extra movement: a push move when a player has three stones surrounding one:

  . . . . . . . .        . . . . . . . .
  . . . . . . . .        . . . . . . . .
  . . . . . . . .        . . . . . . . .
  . . o x . . . .        . . o x . . . .
  . o . o x . . .   =>   . o o x<- . . .
  . . o x . . . .        . . o x . . . .
  . . . . . . . .        . . . . . . . .
  . . . . . . . .        . . . . . . . .

This solves KOs and make group structures much weaker. [T.Sagme, Travels]

Jun 4, 2004

Chinese and Japanese Go rules

The following Go example shows a safe set of stones with two eyes:

   . . . . . .
   . . o o . .
   . o o . o .
   . o . o o .
   . . o o . .
   . . . . . .


Would this set be called a single group even though it is composed of two disconnected halves?

Most players would call it a single group. In area rules it doesn't matter what you call it. In territory rules it could conceivably matter what you call it, (though it doesn't in practice), because territory rules, in all their artificial absurdity, have to refer to groups from time to time in order to define what is considered "dead" and what is considered "alive".

In territory rules, this matters(!). In area rules, it doesn't matter - if there is any dispute you just play it out (and with no cost) until a group or groups is removed from the board.

Logically speaking, you should call the above two separate groups, each helping to keep the other alive. But people never speak so precisely in practice.

There is even a worse situation. The following group has only one true "eye"; the other one, in the NW corner, is a so-called "false eye", and can eventually be filled and the whole lot captured.

   . x x . o .
   x o o o o o
   x x x x o .
   x . x x o o
   x x x x o .


Territory rules actually have to define the concept of eyes, false eyes, and the rest. It is lunacy. (Area rules define nothing - you just play it out to the grim end if necessary). Territory rules, with their defined false eyes, come to grief in this famous sort of position:

   . x x x x x
   x o o o o x
   x o o . o x
   x o . o o x
   x o o o o x
   x x x x x .


Here, black has TWO false eyes, and not a single true one! And yet, both separate groups, or parts of a group, are keeping one another alive; rather like your above example. And even the Japanese admit that black is alive, in spite of what their rule books say!

Basically, territory rules are an abortion. Computers cannot handle them because they are essentially logically flawed. [Bill Taylor]