~Go - Introduction in GO Game - Booklet

Go T he mos m ostt chall challeng engii ng  board game in the world 

An introduction to this ancient and fascinating game

The British British Go Association Association © 1999 1999

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T O YO K U N I III (1786 – 1867) – A CTO RS PLAY PLAYING G O

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TRADITIONAL

JAPANESE G O  B A N  W I T H

ST O N E S M A D E F RO RO M C LA LA M SH E LL LL A N D SL AT E

 Introduction to the game of Go Go is unique among games The history of Go stretches back  some 3000 years and the rules have remained essentially unchanged thro ughout this very very long period. period. The game prob ably originated in C hina or the H imala imalayas yas and myth ology has it that the future of  Tibet was once decided decided over a G o board w hen th e Budd Budd hist hist r uler uler refused refused t o go int o b attle; instead instead h e challenged the aggressor to a game of Go to avoid avoid bloodshed.

are not moved altho altho ugh they may be surroun ded and so captured, in in whic wh ich h case they are removed from the board as prisoners. The players normally normally start b y staking out ou t their t heir respective claims claims to different different parts of th e board w hich they intend eventually to surround and thereby m ake into into territory territor y. H owever, owever, fights fights betw ee een n enemy groups pro vide vide much of the excitement in a game and can result in dramatic exchanges of territory. At the end of the game the players count one point for each vacant intersection intersection inside inside th eir eir o wn territory and one point for every every stone they have captured. The one with the larger larger t otal ot al is is the winn er. er.

In the Far East, where it originated, G o enjoys great great popu larity larity t oday and interes int erestt in t he game game is grow grow ing steadily steadily in Eur ope and A merica. merica. Like Chess, Go is a game of skill – it’s it’s been described as being like four fou r C hess games games going going on together o n the same board – bu t it d iffe iffers rs from C hess in many w ays. The Th e rules of  Go are very simple and though, like Chess, it is a challenge to players’ analytical skills, there is far more scope scope in G o for intu ition. ition.

C apturing aptur ing ston ston es is is certainly certainly one way of gaini gaining ng territory but one of  the subtleties of Go is that aggression doesn’t always pay. The strategic and tactical possibilities of the game are endless, providing a challenge and enjoyment to players at every level and the personalities of the players emerge emerge very very clearl clearly y o n the t he G o board. b oard. The game reflects the skills of the players in balancing attack and defence, defence, making stones wo rk  efficiently, remaining flexible in response to changing changing situations, timing, analysing accurately and recognising recognising the th e strengths and weaknesses of the opponent. In short , Go G o is a game game it it is impossible to outgrow.

G o is a terr territorial itorial game. game. The bo ard, marked w ith a grid of 19 lines lines by 19 lines, may be thought of as a piece of  land land to be shared shared between between t he two players. O ne player player has a supp supp ly of  black pieces, called stones, the other a supply o f white. The game starts starts with an empty b oard and th e players players take turns, placing one stone at each tur n on o n a vaca vacant nt point. po int. Blac Black k pla p lays ys first first and the ston es are place placed d on o n the t he intersections intersections o f the lines rather t han in the squares. O nce played, played, stones 1

What makes Go so special

A brief history of the game

As an intellectual challenge Go is extraordinary. The rules are very simple yet attempts to program computers to p lay lay G o have met with little success; even the best programs fail to avoid making simple mistakes. Apart from beating the computer, Go offers major attractions to anyon e who enjoys games games of skill: skill:

G o is probably the oldest oldest bo ard game game in th e world. It is said said that t he first first Em peror of C hina – himself himself a myt hological hological figure figure – invented invented the th e game in order to improve the mind of his slow-witted son.

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There is great great scope for intu ition and experiment experiment in a game game of Go , especially in the opening. Like Chess, Go has its opening strategies and tactics but players can become quite strong knowing no more mor e than a few basic basic patterns.

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A great advantage advantage of G o is the very effective handicapping system. This enables players of  widely differing differing strengths to play each ea ch other oth er on equal terms withou t distorting the t he character character of o f the game.

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The object object in G o is to make more territory t han the other player player by surro unding un ding it mor e eff effic icie ient ntly ly or by attacking the opp onent ’s stones to greater effe effect. ct. O n such a large board, it’s possible to do somewhat badly in one area but still to win the game by doing better on the board as a whole.

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Every game of Go quickly takes on a character of its own – no two games are alike. Since a player needs needs only t o h ave ave more territory than the oppon ent in order to win, there are very few dr awn games though thou gh the out come may may hang h ang in in the bal b alance ance unt il the very very end.

Altho ugh o riginating riginating in centr centr al Asia, historically it was in Japan that the game really flourished. Introduced into Japan around 740 AD , G o w as initiall initially y confined to court circles but gradually spread to the Budd hist and Shinto Shinto clergy clergy and among th e S Samurai. amurai. Fro m t his auspici auspicious ous beginning, beginning, Go too k ro ot in Japanese society. The Japanese call the game  Igo which has been short ened to G o in the Wes West. t. The Japanese government recognised th e value value of th e game game and in 1612 1612 the to p G o p laying laying famili families es were were endowed with grants grants and constituted as Go schoo schoo ls. ls. O ver ver t he next 250 250 years, the intense rivalry between these schools schools bro ught abo ut a great great improvement in t he standard o f play play. A r anking system system was set set u p w hich divided professional players into 9 grades or dans of which the highest w as  Meijin , meaning ‘expert’. This title could be held held by only o ne person at a time and was awarded on ly if one p layer layer o ut clas classe sed d all all his contemporaries. The most significant advances in Go theory were made in the 1670's by t he  Meijin Dosaku who was the fourth h ea ead d of the H oninbo School School and po ssibly ssibly the greatest greatest G o pla p layer yer in histor histor y. The H ouse of H oninbo was by far th e most success successful ful of the 2

four G o Schools Schools,, produ cing cing more Meijins than the other three schools put together.

introdu ce ced, d, the most import ant being being t h e Meijin and Kisei tournaments. Mor e recent recently ly,, you ng peop le have have turn ed away away from G o as they have have from other traditional elements of  Japanese Japanese cultur cultur e. In spite of th is there are still about 10 million Go players in Japan, some 500 of  whom wh om are profe pro fess ssional. ional.

The whole structure of professional G o in Japan Japan was w as undermined un dermined in 1868 1868 when the Shogunate ho gunate collapsed collapsed and the Emp eror was restored restored t o p ower. ower. The G o college collegess lost their fund ing as as the westernisation of Japanese society society t ook oo k h old. Tod Today ay,, the m ain ain organisation organisation of pr ofessi ofession onal al Go players in Japan is the  N ihon ihon Kiin, which increasingly fosters interest in the game game throu ghout th e world.

In its original home G o is known known as as Wei Q i which means ‘surrounding game’. G o in C hina devel developed oped m ore slowly slowly than in Japan Japan and dur ing the Cultur al Revolution the t he game game suffered suffered throu thr ough gh being regarded as an intellectual pursuit. As a result, it is only recently that th at C hinese players players have matched the strength of the Japanese. Today, Wei Ch i is being re-intro duced in schools and tournaments are held

China

Go in the Far East today The most important G o-playing o-playing countries in the Far East are Japan, China and Korea all of which maintain communities of professional players. players. Major Major tournaments tou rnaments in t hese hese countrie countr iess attract attract sponsorship spon sorship from large large companies comp anies and and a following akin to big spor sporting ting events events here. Unt il relatively recently, the strongest players players from Ko rea and and C hina tended to go to Japan Japan as professionals. professionals. Today od ay they are more likely to remain in their own countrie countr iess where they become national heroes. There are perhaps 50 milli million on G o players players in the Far F ar East and many people who don't play still follow the game with keen interest. O n his retirement retirement in 1938, H oninbo oninbo Shusai ceded ce ded his title to th e ament  N ihon ihon Kiin for an annual tourn ament betw een all leadin leading g players. Since Since then o ther m ajor ajor contests have been

 Japan

Wei Wei Q i – the C hinese hinese characters characters for G o

throughout the country. There is also the annual match between China and Japan which is followed with great interest. With the opening up of  C hina, C hinese professi professionals onals are now frequent visitors at European Go tournaments. Go is also played professionally in Taiwan. H ere G o is known as  Baduk  and is very popular po pular.. Korea Kor eans ns have a reput ation for pla p laying ying very very fast. fast. Fast Fast or o r not n ot they are also also prod pr oducing ucing some of the th e world’ wor ld’ss strongest players. Both China and Korea have a growing population of  very strong young players, a phenomenon which bodes well for the th e futu futu re development development of the th e game. game.

 Korea

 Igo – the Japanese Kanji for G o

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Go in Europe Europe

Go in Britain Britain

Altho ugh th e game game of G o had been described by western travellers to the Far E ast ast in th e 17th 17th centu centu ry it was not p layed layed in Eu rop e until 1880 1880 when a German, O tto Korschel Korschelt, t, wrote a book about the game. After th is some some G o w as played played in G ermany an d Yugoslav Yugoslavia. ia. H ow ever ever the game was slow to spread and it was not until 1958 that the first regular European Championship was held.

Go has been played in Britain at least since since the thirt ies ies but was not played on an organised basis until 1964 when the British Go Association – the BG A – was formed. Today, Today, G o players can can be nu mbered in thousands. There are over 50 Go club clubss in in Britain and th e standard standard of  play compares reasonably with the rest of Europe. Matthew Macfadyen, Britain’s top player in recent years, won t he Europ ea ean n C hampionship hampionship in 1980, 1984, 1987 and 1989.

N owadays, owadays, Go is played played in most Euro pean pean countries. countries. The standard of  play is significantly below that of  professionals in the Far East but the gap is steadily closing as more of the top European players are spending time stud ying th e game game in Japan.

A British British C hampionship hampionship and a British Youth Championship are held every year and there are Go tournaments throughout the country. These often attract upwards of a hundred players, including many beginners beginners and y oun g players. players. An open British Go Congress has been held at a different venue each year since 1968.

In 1992, 1992, a European G o C entre was opened in Amsterdam Amsterdam with suppor t from Iwamoto Kaoru.

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R O U N D AT A R E C EN EN T

BRITISH G O C O N G R ES ESS H E LD LD

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AT T H E

U N I V ER ER SI SI TY TY O F E AST A N G L I A

T he Brit Britii sh G o As A ssoci oci ation ati on Two tru st funds, the C astledine astledine Trust Trust and the Susan Barnes Trust exist to promote the playing of Go by young people.

What What t he BGA does The BG A is a volunt volunt ary organis o rganisation ation which promotes the game of Go in the U nited Kingdom. Membership Membership is open to all all on p ayment ayment of an annual subscription and the BGA aims to suppo rt players of all all standards. Its most important activities benefit all BGA members: members: ❍

A bi-monthly newsletter is sent to all all members.

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Each year members receive 4 issues issues of th e British British G o Jour nal, a magazine magazine of n ews, comm comm ent, instructional articles and game commentaries.

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The BGA makes available a wide selection of books and equipment to members at moderate prices. These ca can n b e ordered by post o r bought at most Go tournaments.

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In conjunction conjunction w ith international international Go organisations, the BGA supports the playing and teaching of Go.

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The BGA h elps elps to attract more players to the game through various various pro mot ional activitie activities. s.

Helping players to improve There Th ere is an an extensiv extensivee programme pr ogramme o f  G o to urn aments aments dur ing the year year, some of which are organised organised by the BGA which maintains a tournament schedule schedule.. O ther to urnaments are organise organised d b y G o clubs, support ed by the BGA in various ways. Most tourn to urn aments are organise organised d in such a way as to allow players of all strengths strengths to take part part by matching matching them th em against against players of  appro ximately ximately the same strength strength . The BGA runs a game analysis service provided by some of the country’s stron gest gest pla p layers. yers. Str Strong ong players are also encouraged to visit clubs to give teaching and simultaneous games, subsidised by the BGA. The BGA also supports teaching visits by profes pr ofessi sional onal G o p layers. layers.

Services for stronger players The BGA records records t he results results of top level tournament games and organises a grading system in which stron g players players achiev achievee promot pro mot ion through d an grades according to thei th eirr res r esults ults in tou rnament play. play.

Services mainly for beginners The BG A mai m aintains ntains lists lists of members and of Go clubs. These are available to members wishing to find new oppo nents. The BG BG A also also encourages encourages the formation of new club clubss – including including scho school ol G o clubs – by providing ‘starter sets’ and advising advising o rganisers.

A three stage British Championship is organise organised d ann ually ually and the BG A also also liais liaises es with with the th e Europ Eur opea ean n Go Federation Federation and the Int ernational ernational Go Federation. A British Youth C hampi hampions onship hip is also also h eld eld annually. annually. 5

How How to pla play G o A l t h o u g h t h e n o r m a l s iz iz e o f a Go board is 19 by 19 lines, it is possible to use smaller sizes. Beginn Beginn ers can learn learn t he basics on a 9 by 9 bo ard and a quick game can can be played on a 13 by 13 board with out ou t losing the essential essential character character of the game. game. The Th e follow following ing examples examples all use a 9 by 9 board.

The rules and an example game A game of Go starts with an empty board and each player has an effectively unlimited supply of ston es, es, one taking the black stones, the ot her taking white. The basic object of the game is to use one’s stones to form territories by surro unding vacant vacant areas of the bo ard. It is also possible to capture the opponent’s stones by completely surrounding them.

stones are placed on the intersections of  the lines lines rather than in th e squares. squares. O nce played, played, stones are not moved altho altho ugh they m ay be captured, in w hich case case they are removed from the board and kept by the captur ing player player as pr isoners. isoners. At the end o f the game the players players count one po int for each each vacant vacant po int inside their their ow n territory and one point for every every ston e they h ave ave captu captu red. The player player w ith the larger larger to tal of territory plus prisoners is the winner.

The p layers layers take tur ns, placi placing ng one of  their stones on a vacant point at each tur n, Blac Black k playing first. first. N ote th at the

Diagram 1 shows the position at the end of a game game on a 9 by 9 board, du ring which Blac Black k captur ed one wh ite ston ston e which had b een een at a.

D iagram iagram 1

Black has surrounded 15 points of  territory, 10 in the lower right corner and 5 towards the top of the board . Black’ Black’ss terr itory includes includes t he p oint a formerly occupied by the stone he has captured. A dding h is prisoner, Blac Black k has a tot al of 16 16 points.

a

White’s territory is 17 points however so White wins the game game by on e point.

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Capturing stones and counting liberties The points p oints wh ich ich are horizon ho rizon tally tally and vertical vertically ly adjace adjacent nt to a stone, or a group grou p of stones, are known as liberties. An isolated stone or group of stones is capt ca ptured ured when wh en all of its liberties liberties are occupied occupied b y enemy stones.

D iagram iagram 2

D iagram iagram 3

b

x x

D iagram iagram 4

x x

x

d

x

x x

c

x

Diagram 2 shows thr ee isola isolated ted w hite stones with t heir liberties liberties marked by crosses. Stones which are on the edge of  the board clearly have fewer liberties than those in the centre of the board. A single stone on the side is reduced to thr ee liberties liberties and a stone in t he corner has only t wo liberties liberties..

Black's next move. Each of these white stones is said to be in atari, meaning they are about to be captured. Diagram 4 shows the po sition sition w hich would arise if Black went on to play at b in Diagram 3. Black has taken the captured stone from the board and in a real game would keep it as a prisoner. The same remarks obviously obviously apply to the oth er two white stones should Blac Black k play at c or d in Diagram 4.

Diagram 3 shows the same thr ee ston ston es of  Diagram 2 each each with o nly one liberty left left and t herefore subject subject to captu captu re on

D iagram iagram 5

Groups Stones occupying adjacent points constitute a solidly connected group. Two Two examp examples les of such solidly connected group s of stones are are shown in Diagram 5. It is important t o remember that o nly stones which are are hor izontally or vertical vertically ly adjacent adjacent are solidly con connected; nected; diagonals diagonals don' t count as connections. connections. Thus, for example example,, the tw o marked b lack lack stones in in th e top left of Diagram 5 are not solidly solidly connected.

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Capturing Capturing groups grou ps of stones ston es

D iagram iagram 6

g

As far as capturing is concerned, a solidly connected group of stones is treated as a single unit. As with isolated stones, a group is captured when all of its liberties are occupied by enemy ston es. es.

h

f 

I n Diagram 6 the groups of Diagram 5 have both been reduced to just on e liberty liberty.. N ote that t he Blac Black k group in the to p right is not yet captur ed because because of the internal internal liberty liberty at f . The two stones at at th e top left of Diagram 6 can each be captured independently at g or h .

e

I n Diagram 7 we see the p osition osition which wo uld r esult esult if  Black captured at e and White captured at f and g . The remaining black stone could be captured at h . As with the capture of a single stone, the points formerly occupied by the Black Black grou p hav h avee become White territor t erritor y and vice vice versa. versa.

D iagram iagram 7

h A player may not ‘commit suicide’, that is play a stone into a position where it would have no liberties or form part of a group which would thereby have no liberties unle un less ss,, as a result, result, one on e or mor e of the ston es surrounding it is captured.

D iagrams iagrams 8 and 9 illustrate the rule governing capture. In Diagram 8, White may not play at i or  j since either of these plays would amoun t t o suicide; suicide; the stones would then have no liberties. liberties. H oweve ow ever, r, if the th e outside liberties have have

been filled, filled, as show n in Diagram 9, then the plays at i and  j become legal; they fill the th e last last b lack lack libert y in each each case and result in the black stones being captured and removed from the board as White’s prisoners.

D iagram iagram 8

D iagram iagram 9

i

i

 j

 j 8

Life Life and and death death and the th e concept of o f eyes I n Diagram 9, White was able to play at i and  j because these plays result in the capture of the adjacent black  stones. Since White’s plays carry the force of capture they don’t count as suicide.

D iagram iagram 10

m

n

A d iffe ifferent rent situation situation is shown shown in D iagram iagram 10. The black  group here could only b e captu captu red if White were able to play at both m and n . Since the first of these plays would be suicide, suicide, there is no way t hat Wh ite can can carr carr y ou t t he captu captu re. These two separate space spacess within th e group are known as eyes.

Any group of stones which has two or more eyes is permanently permanent ly safe safe from captu re and is referred referred to as a live group. C onversely onversely, a gro group up of ston es which which is unable un able to make two eyes and is cut off and surrounded by live enemy grou ps is call called ed a dead it is unable un able to dead group grou p since it avoid eventual capture.

Diagram 11

iagram 11, the black In D iagram black group at the bot tom is in danger danger o f being captur captur ed. To To ensure th at his group has two eyes, Black needs to play at o . If White plays at o , the black group w ill ill no longer be able to make two eyes and cannot avoid eventual capture; White can always fill in the outside liberties and then play at p and q. Black  plays at p or q would only hasten the group's demise.

p o q

iagram 11 is already The black black group at the top left left of D iagram alive even though there is a white stone inside one of its eyes. Since White can never capture the black stones, the white stone caught inside the group can' can' t b e save saved. d.

in D iagram iagram 11, the situation may be left as it is until the end of the game. Then, the dead ston es are are simply removed from the board and counted together together with the captu captu ring player' player' s other pr isoners. isoners.

In the course of a real game, players are not obliged obliged to complete the captu captu re of an isolated dead group once it is clear to both players players that t he group is dead. dead. In this case, once White has played at o

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Thee ko Th  k o rule

D iagram iagram 12

iagram 12, Black can capture a stone At the top of D iagram by playing at r, resulting resulting in the situation at the t op o f  ow ever, r, this stone is itself itself vulnerable to D iagram iagram 13. H oweve captu captu re by a White play at u in D iagram iagram 13. If White were allowed to recapture immediately at u , the iagram 12 and there position would revert to that in D iagram would be nothing to prevent this capture and re-capture going on indefinitely. indefinitely. This Th is pattern of stones sto nes is calle called d eternity – and and two oth er possible possible k o – a term meaning eternity shapes shapes for for a ko , on the edge of the board or in the corner, are also shown in this diagram.

The ko rule removes this possibility of indefinite repetition by for bidding the recaptu recaptu re of the ko, in this case a play at u in D iagram iagram 13, until White has played at least one move elsewhere. Black may then fill the ko but if he chooses chooses not to do so, instead instead answering White’ Wh ite’ss intervening inter vening move elsewh elsewhere, ere, White Wh ite is then permitted t o retake the ko . Simil Similar ar remarks apply to t he other two positions in these diagrams; the corresponding moves at w and v in D iagram iagram 13 must also be delayed by one turn.

r t

s Diagram 13

u

w

v

Seki - a kind of local stalemate Usually a group which can’t make two eyes will die unless unless one of t he surro unding enemy grou ps also also lacks two eyes. eyes. This often leads leads to a race to capture bu t can also also result in a stand-off situation, know n as seki, in which neither group h as two eyes but neither can can capture the other due to a shortage of liberties. Two iagram 14. N either examp examples les of seki seki are shown sho wn in D iagram either player can afford to play at x , y or z since to do so wou ld enable enable the other t o make a captur captur e. N ote that even though t he groups involved involved in a seki seki may have an eye, as a general rule none of the points inside a seki count as territory for either player.

D iagram iagram 14

x

y z

The end end of th e game The game ends by agreement – when neither player believes that he can make mor e territory, capture capture mo re stones or reduce his opponent’s opponent’s territor y by

playing playing on. A player player w ho considers the game to be over may pass instead of  playing a stone and two consecutive passes passes end the th e game.

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The handicap system As remarked in the introduction, one of  the best features of the game of Go is its handicap system. A weaker player may be given an advantage of anything up to nine stones which are placed on the board in lieu of his first move.

in terms of stones, the num ber of stones for the handicap is simply the difference in grade between between th e two players. players. There is an establis established hed patt ern for the placement placement of hand icap icap sto nes, represented represented by the dots which may be found marked on any Go board. This is shown in Diagram 15, seen from the Black player's point of view view.. For handicaps handicaps of two or thr ee stones, where the stones can' can' t be placed symmetrically, the convention is that the far left corner is left vacant.

Thr ough th e grading grading system, system, any any t wo players can easily easily establish t he diff d ifference erence in their strength and therefore how many stones the weaker player should t ake in ord er to compensate for for the difference difference in strength. Since a player's grade is measured

Diagram 15

Japanese and Chinese rules of Go The r ules desc described ribed in t his booklet are the Japanese rules and these are the rules most commo nly used in the West. West. The Chinese use a different system of rules

which are essentially the same but which not ably involve involve a diff different erent metho d o f  counting the score. The two sets sets of ru les les usually lead to the same game result.

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 An example game of Go G o is norm ally ally played played on a 19 by 19 board bo ard (not e it’s it’s 19 lines lines not 19 squ squares) ares) but smalle smallerr boards are recommended for beginners. Even boards as small as 5 by 5 can provide an interesting game and 9 by 9 or 13 by 13 boards are often used even by strong p layers layers for a q uick game. game.

first reading. Try to see how the players use the thr eat eat of captur e to d evel evelop op t heir positions. N otice also also how they tr y to connect their ow n stones and separate separate those of the opponent. Most games of Go start fairly peacefully with each each player loosely loosely m apping out territory in different parts of the board. O n a full size size board p lay lay usually usually starts in the corners. In this example on a small board, Black chooses to play his first move in the centre.

The example game shown here is played on a 9 by 9 board and illustrates illustrates most o f  the rules in action. It's a game played between two professionals so don’t expect to grasp all that is going on at a

The numbered stones in the figures show the order in wh ich ich t he ston es are are played. In later later figures, figures, stones which have alrea already dy been played are not n umbered. um bered.

With 1 and 3 in Figure 1, Black Black exerts influence over t he right side of the board while with 2 and 4, White lays claim to the top left corner. With 5 Black aims to exclude White from t he bot tom half of the board. White leans leans agai against nst th e lone black stone with 6, reducing it to two liberties. With 7, Black strengthens his stone at 5 by extending to 7 and now his group has 4 liberties.

Figure 1 (1 - 7)

4

6

I f Figure 2 seems somewhat alarming, you may find it easier easier to look back at Figure 1 and imagine adding adding th e stones one at a time. Better still, play the game out on a board.

12

3

5 7

After t he 8 – 9 exchang exchange, e,White White pu shes tow ards the b ott om with 10 but r ather than d efending efending the botto m left left corn er, er, Black changes direction with 11, now trying to fence off  the top right. Again White leans against the black stone and again Black strengthens his stone by extending to 13. White pushes into the gap with 14 and Black blocks at 15. If Black succeeds in surrounding all of the area to the right and bot tom of the board , Bla Black ck will have mor e territory than W hite has in the to p left. Accord Accord ingly ingly, White cuts Black into two with 16, aiming to destroy the Black area at the bott om in the course of this attack. attack. N ote that the three black stones to the left of 16 now have only two liberties.

1

2

Figure 2 (8 - 16) 12 11 13

8

10

14

9

15

16

Figure 3 (17 - 21)

Blac Black k mu st do something to avoid the imminent capture of  the th ree stones cut cut off by Wh ite 16. 16. In Figure 3, Black 17 and 19 are both t hreats to capture White wh o flees flees in tur n with 18 and 20 (can you see why 17 and 19 are threats?). With 21, Black has stabilised his group and White's three stones are trapped inside Black's sphere of influence. The ou tcome of the game now h inges inges on t he fate fate of th ese ese stones. If th ey die and and W hite obtains no comp ensation, ensation, White will lose. If they live, or can be sacrificed in order to reduce Black's territory, White can still win the game.

18 21

White Whit e plays 22 in in Figure 4 in an attempt to expand expand his position along the edge and and to reduce the liberties liberties of the black stone at a. Black blocks at 23, preventing White from forming a living shape along the second line. With 24, 24, White th reatens to play at 25. Du e to the pr esence esence of  22, 22, this move would simultaneousl simultaneously y t hreaten th e captu captu re of the black stone at a and of the tw o stones to t he left left of  25. Since either of these captures would save the white stones below, Black plays 25 himself, putting an end to any possibility of the white stones' escape. Unable to escape and with insufficient space to be able to form t wo eyes, White plays plays 26 on t he out side. side. H is plan plan is to sacrif sacrific icee the stones on the r ight ight and in t he pro cess cess to destroy Black's prospective territory at the bottom.

17

20

19

Figure 4 (22 - 26)

23 25

a

22

24

26

Figure 5 (27 - 39)

Figure 5 shows White's plan put into effect. Black really has no choice about 27. Black would like to defend the stone to the right o f 26 but if White gets gets the chance to block at 27, Black's advantage in the fight will be lost. White's plays at 28 and 30 are a device to increase the value value of t he sacrifice; sacrifice; Black Black mu st play at 31 to p revent White from getting getting an eye by playing playing there.

37

35

31

30

With 32 and 34, White captures Black 21 and now Black  must capture the sacrificial white stones with 35, 37 and 39 while White creeps creeps along along the bott om w ith 36 and and 38. N ote that a play to the right of 38 is White's privilege. It is not urgent since Bla Black ck cannot p lay lay t here. Can you see see why ?

34

With 39, the fight in this part of the board comes to an end. Although White has lost 7 stones, he has captured one of  Black's Black's and succeeded succeeded in destroying t he botto bo tto m area, eve even n making a couple of points of territory in the bottom left corner. Fur thermo re it is still still White's tur n to play and he is free to take the initiative elsewhere: to expand his own area or reduce his opponent's; to exploit Black's weaknesses or to patch up his own.

Before looking at the next figure, try to decide for yourself  where it is most profitable for White to p lay lay next.

13

32

33 36

27 38

28 29

39

If you r guess for Wh ite's next move was somewhere somewhere near White 40 in Figure 6 you can can congratulate you rself. rself. This is where the bo undary between White' s territor y and Blac Black' k' s is still still most uncertain and t he first first to play here will make the greatest gain. White 40 removes White's only weakness, the possibility of a Blac Black k cut at th e same same point. I t also prepares for Wh ite to slide into the top right which would destroy pro spective spective Bla Black ck terr itory there.

Figure 6 (40 - 45) 44 40

42

43

41

45

Black 41 blocks White's path and 42 to 45 complete the boundary between the two territories here. The game is is almost almost over. over. C an yo u see the best place for White to play next? next? White Wh ite 46 in Figure 7 pushes into the one remaining gap in Black's wall. Black 47 shuts White out and 48 prevents the capture of 46. Strictly speaking the game is over at th is point since there is now here either either player player can can play wh ich ich w ould increase increase his own terr itory or decrease decrease the oppo nent' s. Bla Black ck wo uld like to p lay lay at 50 but if he did did so, the black stones would have only one liberty and White would capture them with a play to the right of 50.

Figure 7 (46 - 50)

48

Black Black 49 and 50 complete t he for malities. malities. After 49 and and the removal of the 6 white stones, Black could play at 50. 50. This wou ld make the p oint t o t he right o f 50 Bla Black  ck  territory, so White plays at 50 to prevent a Black play there. Similarly, the moves in Figure 8 make no difference to the score but are played played t o clarify clarify th e situation situation and make counting easier. It is not necessary for Black to complete the captu captu re of the w hite stone at a – White admits that it is dead. dead. Th ere is no point in either player playing inside the other's territory. Territory is so called precisely because it is an area which is secure against invasi invasion. on. An y ston e the op pon ent played inside inside it wou ld be kille killed. d. N either either p layer layer could hop e either either to form a living group inside, or to escape from, the oth er' s territory. N either either can the players players hope to kill any of t he opp onent' s stones. All All their stones – exce except pt White' s dead dead stone at a – are effectively effectively conn ected, forming living groups with at least two eyes.

14

46

47

49

50

Figure 8 (51 - 52)

a

52

51

The result of the game At the end o f the game, game, any any dead stones are are removed from the bo ard. This results results in the po sition sition show n in Figure 9.

Figure 9

There Th ere are 18 vacant vacant int ersections inside Black’ Black’ss terr itor y and Black has taken 7 prisoners altogether, making a total of 25 points. White’s total is only 20, made up of 19 points of territor y and 1 pr isoner isoner so Black Black has won the game on the board by 5 points.

The process of counting is usually simplified as shown in Figures 10 and 11. Step 1

Step 2

Step 3

Any neutral points, that is unoccupied points which lie between black stones and white stones, are filled by either player. In this game there are no n eutral points to fill fill.. Each player puts his prisoners into his opponent's territor y. This produ ces ces the position shown in are reduced by Figure 10. The players' t erritories are one po int for every stone th ey have lost. The t erritor ies ies may b e re-arranged to faci facili litate tate counting. This produces Figure 11 in which wh ich we see that Black has 17 points and White has 12 points.

The scores in this figure are the result of each player subtracting from the value of the opponent's territory the numb er of prisoners he has captu captu red, rather th an adding them to his own to tal but th e end result result is the same: same: Black wins by 5 points.

 Komi Black Black has a nat ural ur al advant advantage age in in p laying first first and in games between players of the same strength it is usual to comp ensate ensate White for the disadvantage of playing second by deducting points from Black's score. These points are called komi and from experience in in actual actu al play, play, the value of h aving aving th e first move can be assessed at about 6 points on a full size board. O n a nine by nine board, komi is nearer 8 points. Looking again at our example game, although Black has won the game on t he board b y 5 points, if komi were 8 points then W hite would w in the game game by 3 points.

15

Figure 10

7 5

6

4 1

3 2 1

Figure 11

Go Problems H ave ave a go go at t he follow following! ing! Prob lem lem 3

Proble Pro blem m1

The Black group in this diagram cannot escape White's encirclement. If these stones are to live, live, they must make two eyes. Where should Black play to guarantee two eyes for the black stones?

Black to play There is a clever way for Black to capture thr ee white stones, stones, if if you can can yo u find the right m ove.

If it is White' s turn , can can yo u see where to play in order to kill the Black Black group? There is more than one way to do this.

Proble Pro blem m2

Prob lem lem 4

White to p lay lay There is a way for White to captu captu re five five black stones. You need to read a few moves ahead to see the answer to this problem.

In this fight, fight, thr ee white stones are vulnerable vulnerable to capture. Fro m w hich direction should shou ld Black Black give atari atari in ord er to captur e these stones?

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