(copied from from www.kuro5hin.org without permission)

Go: Life Itself

By GoStone
Thu Jul 11th, 2002 at 09:36:19 AM EST

Saying 'just one game'
they began to play...
That was yesterday
Japanese senryu poem

There is one board game that stands above all others. The most beautiful, most ancient, most strategic, most subtle. The king of games. A game which teaches as much as it entertains, whose enthusiasts number tens of millions and which has often been compared to life itself.


Curiously in our little multicultural global village, the game is only faintly detectable on the periphery of the western cultural vision; mentioned in passing in novels, and seen briefly in movies (Pi, A Beautiful Mind), where it tends to symbolise an esoteric intellectualism. Geeks may know it only for its resistance to computer attack. Mathematicians may know it provided the inspiration for Combinatorial Game Theory, and the Surreal numbers. But despite an estimated 100,000 players in Europe, and a similar number in the USA, it is fair to say that most people have never even heard of the game. On this basis, l'd like to introduce Kuro5hin to the game of go.

"The Master said, 'Hard is it to deal with him who will stuff himself with food the whole day without applying his mind to anything good. Are there not gamesters and go players? To be one of these would still be better than doing nothing at all.' "
Confucius (who had better things to do)

Go is thought to be 3,000 to 4,000 years old, making it contemporary with Stonehenge. It began in China, where it is now known as Wei'Qi, possibly growing out of the same framework as acupuncture, shiatsu and feng shui. About 1,300 years ago it spread to Japan, where it blossomed, being sponsored by the medieval state and becoming an essential samurai art. Most recently the best players have come from Korea, where it is known as Baduk and an estimated one person in ten plays the game regularly. In total there are 25 to 50 million go players in the Far East.

Through these long millennia and cultural wanderings there has been little alteration to the rules. No other game can make a similar claim to longevity and stability. And for good reason. The rules of go are so simple, yet so perfect, that it cannot be tinkered with without destroying it. Like a mathematical truth, go appears to have always been there, beyond time and space. It has been conjectured that if there are sentient beings on other planets they may also be playing go.

Traditionally go is played on a polished wooden board (known as a Goban), marked with a square grid in thin black lines. Nineteen lines in each direction by convention, though sometimes smaller boards are used for a quicker game. Each player has a bowl of lens-shaped 'stones', actually made of slate for the black and shell for the white stones; 180 stones each, effectively an unlimited supply.

"That play of black upon white, white upon black, has the intent and takes the form of creative art. It has in it a flow of the spirit and a harmony of music. Everything is lost when suddenly a false note is struck, or one party in a duet suddenly launches forth on an eccentric flight of his own. A masterpiece of a game can be ruined by insensitivity to the feelings of an adversary."
The Master of Go, by Yasunari Kawabata, winner of the Nobel Prize for Literature

A game starts with an empty board, like a bare canvas before two painters. Starting with Black, the players alternately place single stones on the intersections of the lines, gradually filling the board. Once played, the stones do not move, unless captured and removed. With time the image of the game reveals itself like a landscape through a mist, now this detail, now that, where what seems clear now may later be revealed as illusion.

For a while a sequence of stones may be played close to one another like the cut and thrust of a sword-fight. But suddenly, seemingly unpredictably, play jumps about the board to distant, unconnected regions. To some extent you can tell how good a player is by the fractal quality of his play; a poorer player will spend too long detailing an idea, where a master will sketch it lightly before moving on. By the end of the game the stones press closely against each other forming "a map of the contest of two minds".

"Lose your first fifty games as fast as possible"
Go proverb

There are only three rules in go. But that is only the beginning. These rules have implications, and the implications have implications and so it goes on, until after ten years of playing it still feels like you are learning the game. There is often a period of frustration between learning the rules and working out what you are trying to achieve. So, on the understanding that these rules alone leave much unsaid, let me explain.

The first rule says that when you're surrounded, you come off. As stones sit on the intersections they generally have four lines radiating out from under them to neighbouring intersections (except on the edge where there may be three or even just two neighbours). If a neighbour is empty it is called a 'liberty', or a 'life'. If all its lives are taken by the enemy a stone is captured and removed. Captured stones count one point, and are usually stored in the lid of the same bowl a player stores his own stones in.

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

the black stone at x has one liberty

. o . .
o x A .
. o . .

if white plays at A he captures the black stone

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

now the board looks like this

If two stones are adjacent they both live or die together. To capture them, you must occupy all their liberties. A group of stones like this can be any size.

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

this group of black stones still has three liberties

. o A .
o x x B
. o C .

if white gets to play A, B and C he captures two stones

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

like this

Using this principle it is often possible to evade capture by 'running away', i.e. building a bigger group with more liberties. But a bigger group doesn't necessarily mean more liberties, and it is quite possible to run into trouble rather than away from it.

. . . . .
. x x x .
. . . . .
. x x . .
. x x . .
. . . . .

two black groups, each with eight liberties, though one is bigger than the other

A further complication is that while White is surrounding Black, Black might be surrounding White in a life or death struggle. Whoever gets there first will remove the captures, freeing up liberties for his own stones. Certain common formations are actually impossible to capture.

"The game of go is a vast territory for which the map will never be complete"

All in all, capturing stones is not easy. They tend not to lie still and accept their fate. And this is where the second rule comes in. Surrounded empty intersections also count one point each, called territory.

. x x . .
x . . x .
x . . x .
. x x . .
. . . . .

four intersections surrounded by black

Now territory is much easier to surround because it doesn't run away or fight back, and there are huge swathes of it to go for right from the start. So go is a game of territorial acquisition, often described as like two races settling a new land, or even two companies trying to capture a market. The emphasis is upon speed, efficiency and lightness, dropping stones into empty spaces to stake a claim, then leaving them to prove themselves.

So you play your stones, but paradoxically it is not your stones which matter. You don't want them captured because they allow you to surround territory etc., but they have little worth of their own. During the course of a game many stones will be sacrificed deliberately by both sides. This may offend modern notions of justice, and it certainly confuses play. The stones can blind, swarming like flies. You know you can kill some, and some will have to live, but which? Beginners will often, from pity, try to rescue stones that were serving more effectively in sacrifice. The temptation to become 'attached' to your stones, in the Buddhist sense, increases as the groups become larger.

"The board has to be square, for it signifies the Earth, and its right angles signify uprightness. The pieces of the two sides are yellow and black; this difference signifies the Yin and the Yang; scattered in groups all over the board, they represent the heavenly bodies. These significances being manifest, it is up to the players to make the moves, and this is connected with kingship. Following what the rules permit, both opponents are subject to them; this is the rigor of the Tao."
Pan Ku, 1st century historian

One verse of the great Tao Te Ching asserts the value of nonexistence, showing that the utility of a cup is the emptiness inside it, and the utility of a wheel comes from the inner hole on which it turns. These deep metaphors are found reflected in go. At a simple level, it is not the number of stones connected into a group that determines whether it lives, but the number of empty liberties you haven't played on. Similarly your stones do not add to your score in any way, only the empty territory they surround. Playing additional stones in your territory actually deducts from your score.

"Yield, and maintain integrity.
To bend is to be upright;
to be empty is to be full"
Tao Te Ching

Taoism stresses that flexibility and change are vital. This is fundamental to go, as is the Tao's emphasis on harmony and balance. Enthusiasts of Judo, Tae Kwan Do and other eastern martial arts will understand these ideas. Go, too, was considered a martial art by the samurai, and the more you understand go the greater becomes your appreciation of these Taoist principles.

"If this were go
I'd start a ko fight
and surely live,
but on the road to death
there's no move left at all."
Poem attributed to Sansa, the first Honinbo (leader of a prestigious Japanese go school) and founder of that line. He is said to have composed it on his deathbed in 1623.

There is a certain formation of black and white stones whereby one player can capture a stone, but is then liable to immediate recapture, returning the board exactly to its previous position. The captures could therefore repeat indefinitely. This formation is not unreasonably called 'ko', the Japanese for eternity. It occurs frequently, usually many times in a game. Even worse, ko situations can arise where it is worth a lot of points to be the last person to capture. Given the choice each player might repeat indefinitely.

The third rule provides an orderly escape. It says that after player A captures a stone in a ko, player B cannot take back immediately. He must play at least one move elsewhere first. This gives A an opportunity to destroy the ko formation. If he doesn't do so, and the ko still exists on B's subsequent turn, the roles may reverse. B may take back, forcing A to 'play away' for a turn.

It is not all bad for the person who has to play away from a big ko. If he can find somewhere on the board where two consecutive moves would be worth even more than winning the ko, the other player will be forced to respond, leaving the ko intact and available. Good players deliberately leave situations unresolved across the board to be used like this as 'ko threats' later, and a ko can develop into a complex fight. Or if a situation is resolving adversely for a player he may abandon it early, aiming to rescue it later with the two free moves that a ko fight offers.

"Go is to Western chess what philosophy is to double entry accounting"
Shibumi, bestseller by Trevanian

To many go players chess is the 'c' word, but the main reason to mention chess in a go article is not to disrespect it, but to provide a reference point. The two certainly seem like diametrical opposites. Chess has complex rules, go simple ones. Chess eliminates, go accumulates. Chess pieces are hierarchical, go pieces are equal. Chess is a battle, go is a war of many battles. Someone famously wrote a PhD thesis on the theme that in the Vietnam war, the Vietcong were using go strategy while the US military were playing chess. Personally I like chess, but I think go is in a different league.

My favourite theory is that chess is a variant of go. Despite the received wisdom that chess was invented in India or, even less likely, Persia, there is evidence to suggest its origin may actually have been China. There are more chess-variants in the Far East than anywhere else, and there is controversial documentary evidence in China that precedes anything in India. As it happens, Chinese chess, called "Xiangqi", is the only variant played with small round medallions inscribed with the name of the piece. It is also the only variant played on the intersections of the grid rather than inside the squares. The board has 9 x 9 intersections, like many small go boards, which corresponds to 8 x 8 squares. I'm not sure if anyone believes this but me (and you?), but it is such a neat idea I would be disappointed if it were disproved. It may be that go, chess, backgammon and playing cards were all invented in China.

"A bad plan is better than no plan at all"
Go proverb

"In the beginning, have no plan"
Go Proverb

Emanuel Lasker, an early chess grandmaster and one of the first western go enthusiasts, wrote "Chess is 99% tactics". He, like many others since, was impressed by the contrasting strategic depth of go. Now go, like chess, provides situations where the ability to read ahead is of paramount importance. It even has a vast body of TsumeGo problems, equivalent to the chess problems found in newspapers, and equally mindblowing. But in go the tactics are nothing without a separate strategic vision, which must be revised continually through a match.

Go is often referred to as "intuitive"; not because it is obvious to one and all, but because it is often not easy to explain rationally why one move is better than another. It is simply impossible to follow through all the continuations, so it comes down to experience. To help the task, Go has developed a large vocabulary of esoteric terms such as influence, aji - literally 'flavour', thickness, sabaki - 'lightness', and a folkloric list of proverbs, many of them conflicting, but nonetheless true for that.

"Studying go is a wonderful way to develop both the creative as well as the logical abilities of children because to play it both sides of the brain are necessary."
Cho Chikun, among the world's strongest players and one of the three great prodigies in go history

It is the intuitive nature of the game that makes it so hard to program. Currently the best programs on the fastest computers play little better than beginners, though the financial rewards for improving on this are huge. For twenty odd years (until the recent death of the donor) there was prize of $1 million for a program which could beat a professional player. This goal is still unlikely in our lifetimes.

The basis for computers playing games is the Minimax algorithm invented by Claude Shannon, which examines the tree of possible moves and counter-moves up to the limits of allowed time and computer resources. It evaluates all the positions reachable at the outer edge of the tree, and then uses the algorithm to prune the tree back down to the best first move.

The problems with computer go start with the size of the tree, due to the large number of potential moves. Chess has an average 30 or so legal moves per turn, generating of the order of a million possible positions within 5 moves. But go has an average of about 250 legal moves per turn, generating of the order of a thousand billion positions. The real problems begin, though, with the evaluation function. Computers have great difficulty deciding which is the better of two go positions, and cannot even reliably say who is the winner when the game is over.

Nevertheless, there are a number of programs available for beginners to practice against. Gnugo for Unix is the open-source choice (join the development team!). Igowin for Windows has an excellent built-in tutorial for beginners, and is free in the beery sense (burp).

"Often times at my go club, enraged old men will take the Goban and hurl it against the wall. This not only causes loud noises and distractions but also many injuries due to the flying stones. The old man then uppercuts his opponent and storms out of the room. If the man is seriously injured, he must wait until a member of the club is not playing a game before he can receive help. This is one of the worst habits in my opinion. Main Reasons:
  • Death or serious injury may be caused to your opponent.
  • Rushes all other games because the players are hurrying to finish in order to give the injured opponent proper medical treatment.
  • Less boards to play with in the club.
  • Less appealing club location due to dent in wall."
Posting to the brilliant Sensei's Library, under the section "Bad Habits"

Internet go servers are the safest way to play! They are bringing go to a new audience. The Kiseido Go Server (KGS) is friendly to beginners and has the best client and protocol. Log on as a guest and just watch some games. Be baffled! IGS is where the pros hang out. The Dragon go server is good for games at email speed. Most servers will even calculate your rating automatically after you've played a few games.

"There are nine mental levels into which players are distinguished. The first is called 'being in the spirit', the second 'seated in enlightenment', the third 'concreteness', the fourth 'understanding changes', the fifth 'applying wisdom', the sixth 'ability', the seventh 'strength', the eighth 'being quite inept', and the ninth and last 'being truly stupid'."
The Classic of Weiqi in Thirteen Chapters, c.1054 AD

The rating system was developed originally by the old Japanese go schools and is now used universally despite differences in calibration between countries. It allows players of different strength to play even games by giving the weaker player free moves ("handicap stones") at the beginning; the number being determined by the difference in grade between the two players. Traditionally there is a formal placement for these stones, to a maximum of nine.

Experts are assigned a "dan" rating, rising from 1 to 9-dan. A 9-dan player should therefore give a 1-dan player eight free handicap stones for an even game. There are not many 9-dan amateurs, but professionals have a separate, stronger dan scale, where a 1-dan professional is about the same strength as a 7-dan amateur. There are many great 9-dan professionals, though the professional scale doesn't really relate to handicap stones.

The rest of us get to play on the nursery slopes. We have our own "kyu" scale which runs in reverse from a complete beginner at 30-kyu up to 1-kyu, which is one point weaker than 1-dan. Again, every point on the scale corresponds to a free handicap stone. As a 5-kyu player with many years experience, I could start with twelve free moves against a top professional and still probably lose.

"Monks who have a talent for it play go with women and become their lovers."
Yamaoka Genrin (1631 - 1672), Edo-period essayist

To buy your own lover-board, try Kiseido, Samarkand or Yutopian.

For further reading, download The Way to Go by Karl Baker. A more in depth introduction is given in Go for Beginners by Kaoru Iwamoto, but there are dozens of other beginner's books to choose from.

The British Go Association and the American Go Association also sell equipment at a discount to members, as well as providing lots of other real and virtual resources, including downloads. The European Go Association can help you locate your nearest european club.

Jan van Steen's go site is encyclopaedic, up-to-the-minute and very well presented. Play through the latest tournament games one move at a time.

Other interesting sites include the Mind Sports Olympiad, Milton Bradley's go pages, Harry Fearnley's go pages, and the rec.games.go newsgroup.

The Go Teaching Ladder is an neat way to improve. Send in your game records and the contributors here will review them for free. Also try the online Interactive Go Tutorial.

If you are prepared to pay for tuition, Guo Juan is the real thing. A 5-dan chinese professional living in Holland, who runs an internet based go-school. She sometimes gives demonstration games on the Kiseido Go Server too.