1975 U.S. Computer chess championship

94 Pages·1976·2.431 MB·English

by  David N. L Levy

1975
V.SCo.m puter
ChesCsh ampionship
1975
U S ComputeCrh esCsh ampionship
. .
byD aviLde vy
ComputSecri ceenP re,sI snc.W oodladn HillCsa,li fornia
11
Allr ighrtess erveNdo.p art ofth isw orkm ayb er erpoducetdar.n smietdt.o r
storienda nyf ormor bya ny meanwsi,t hotuhtep r iorwr ittecno nsenotf t he
publiesr.h
ComputeScire nceP r.,:ss,I nc.
456Poe6 Aveneu
WoodlnadH ills.C alifornia
91364U SA
Firpsutb lis1h9e7d6
Copyrti© g h1967 ComputSceire nceP resIsn,c .
ISBN0 -914894-00-(5h ardbound)
0-941894-01(-s3o ftbound)
l.ibrayrofC ongerscsa talongu mber:76 -241
PhotosetbtyiQn ugi ckset
1841-86O,l dS treeLotn,d oEnC l
Print eidn t hUen itde Sttae osf A merica
iii
Contents
Introduction
HowC omputerPsl ay Chess 1
A BrieHfi stoorfCy h esPsr ogramming 4
TheS ixth U.S. CCohmapmuptieorn sh.i p.. . . . . . . . . . . . . 8
.
TournamenRtu les. .... .. . . . . . . .. . . . .. . . . . . . . . . . . . 8
The Competi.t .o rs.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 10
TheS wisSsy ste.m. .............................1.2.
Tab leo fR esults. . . . . . . . .. . . . .. . . .. . . . .. . .. . . .. .. . 13
ROUND ONE. . . . . . . . . . . . .. .. 1 4. . . . . . . . . . . . . . . . . . . .
ROUND TWO . . . . . . . . . . . . . . .. .. 2 .2 . . . . . . . . . . . . . . . .
ROUND THREE .. . . . . . . . . . .. ..29 . . . . . . . . . . . . . . . . . .
ROUND FOUR . . . . . . . . . . . ... 54 . . . . . . . . . . . . . . . . . . . .
Appendix I-TShiem ultaneEoxuhsii btio.n .. . . . ... . 6 2. . . .
Appendi2x- A Descriptoifto hneC hampio.n. ........ .7.S
TheF uture. . . . . . . . . . . . . . 84. . . . . . . . . . . . . . . . . . . . . . ..
Bibligoraph..y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 86
Preface
The1 97U5 . SC.o mputeCrh esCsh ampoinshiwaps t hes ixitnht hes erioefs
tournamenotrsg anizbye dt heA sscoiant ifoorC omputinMga chienryT.h e
torunamentsha vaeL bLe esno s uccestshfauttLhs i e venhta sc ome bteor egarded
aso neo ft heh igshp otosf t hea nnuaAl.C .M. confereIntci esp. a rticLauLry
intesrteitnogw atcwhh atp rogreissms a dei nt hiisn teresfiteiLbndeg t eweno ne
yeaarn dt hen exta,nd I h opet hatthi sb ookw iLL tghierv eea dae fra ir idea of
thset aotfet haer itn 1 97I5a .L shoo pet hamta nyo ft hega mesw ilptr ovteo b e
enterntianiags w elalsi nteresting.
Lnm y introtdinuo chIa ve giav berni eexfp Lnaatioofnh owc omputeprLsa y
chesssot hat tuhnei nitiraetaerddw e ilbLe a blteo u ndersttahned bouflk the
text ftolhlaotw Ish .av aeL sgoi veans horhits rtyoo fc ompuetrc hesTsh.o esw ho
wistho f inmdo red etaoinLe si thoerbr o tohf t heeas specotfts h seu bjecsth odu L
consuLmty book" Chessa ndC omputerwsh"i cihs apLusbosl ihedi nt heU . S.A.
and Canadbay C omputeSrc ienPcrees s In.c.a nd inE uropaen dt heB ritish
CommonweaLbtyhB .T.B atQsrfdL td.
Is huoldl ikteo thaHinLka rTyh omaws hot ypedm osto fm y manuspctr,i
DavidS Lataen dL arrAyt kni whos uppLiesdo meo f theiprro garm'so wn
though(tasn dt hes ourcmea terifaoLrA p pendi2x)a ndM ozeLlLoeh nsoGanT,Y
Booasn dA lina Gort!wiheobk .i ndtloyo k pthhoet ograaptmh ysr equeAsbto.v e
aLLI shoLuilkdte o t hanmky p ublirs hfesourg gesttihnipgsr ojeicntt h ef irst
placaend f oars kjnm�e tou ndertaik.te
DavidL evy
LondonN.o vembe1r9 75
INTRODUCTION
Introduction
HowCo mputers ChPeslsa y
A comptueirs a high-spceaeldc uladteviincgwe h icihs ca pabloef s toring a
vasatm ounto fn umerailci nformna.tp ieorformairnigt hmeatnidc logical
operatioontn hsi isn formaatnidor ne gurgnigtt ahteri eusltosft hec alculations_
Byu sinogn es toralgoec atifoonre acho ft hes itxy-fousrq uaroens t hec ness
board,an db yd enotian wgh itpea wnb y( say1).a blacpka wnb y- I, a white
knigbhyt2 ,a blakc knigbhyt- 2,e ct.i,ti sa simpmlaet tetrom akea computer
appeaarb lteo r emembae corm pletceh espsos iotni.w henw hati ti sa ctulayl
doinisg storisnitgxy -fonuwnrb ers (emspqtuya raerse u sualdleyn otebdy
zerosI)ft. h es quaraersen umbere(df oexra mplef)r omi t1h rou1g8h, 2 1
throu2g8h,e tc(.s,e e diagirtia spm o)s,s itbold ee reis vimprluel tehsa etn abal e
computteroc alculwahtaemt o veasr epo ssilbei na g ivepno sint.i o
BLACK
WHITE
1
1975U .S.C OMPUTERC HESSC HAMPIONSHIP
Thusa. k nigshitt uaotnes dq uarn ea ttcakst hes quarne msi nu2s1 .n minus
19,n minu1s2 n, m inu8s,n plu8s, n plu1s2 n, p lu1s9 a ndn plu2s1 p,r ovided
thatth esneu mberhsa vbeo tdhi giitnts h rea ng1e t o8 .
Beinegn doewdw itthh ea biltiotr ye membpeors itiaonndst og eneraatlel
legmaolv efsr oam nypo sitioanc ,o mputcearn "thaihneka dc"r,e atfuirni gt self
alpols sibpolsei tioantas n yd esirleedvo efll ook·ahead.
Ift hen umb ero ff easible chessn ogtsoa meenso rmwoausas c ,o mputweoru ld
be abtlope l apye refctc hesIstc. o uladn alytzeh ei nitpoisailt ioountt om ateo r
toa mandatodryr awpons itioatnt het erminaotfieo vne ryl inoefl ook-ahead
analysBiustt. h en umbeorf po ssibglamee s (morteh an1 012f0)a re xceetdhse
numbeorfa tomisn t huen ivearnsdet htei mtea ketnoc alculjautset moonveei n
thpe erfect wgoaumlbede m easuriendm illioonsfy ears. Clsoemaer cloyr,n ers
mustb ec utTh.e deptohf l ook-ahmeuasdt kbeep tt ol esssu per-human
dimensiaonndts h eev aluatoifto hneso -call"etde rminal pos(itthiooasnttes h "e
deepelsetv eolfl ook-aheamdu)s tb e moreso phistictahtaendm ereltyh e
recognitni oofm ateo ro fa no bligadtroaryw .
Toa ssetshsem eriotfa chesposs itioanp .r ograemm ploay dse viccael 1ae d
scorinfgu ncti(ooernv aluatifounnt cionwh)i ccha na ssiagn nu merisccoarle t o
anyp ositiTohni.ss c oriesi ntendteord e flecwth icshi dhea st hea dvantaagned
the magnitudaed voafn tiaThtgese .sc orei sc alculbatyfe idr dsett ermitnhien g
quantiotfv ya riofuesa turseusc,ha sm aterimaolb,i licteyn,t ceorn treotlc,. ,
possesbsyee da chs idea,n dt hecno m biningq utahnetsieit niteaos w eighted
sum.t hew eightirnegfsl ectthienr ge latiimvpeo rtaonfct eh ef eaturFeosr.
examplet.h em atermieaals urmeig hbte a rriveadtb yco untinogn ep oinfto ra
pawn. tfuhrra e ek nigohrtb ishofpi.vf eo ra rookn,i nfuer a queena.n do ne
milliofno ar kingM.o bilmiitgyh sti mpbleyt hne umbero fm ovetsh aatp layer
canm akep rovidietid sh ist urtno m oveA. primitsciovrei nfgu nctiwoonu ld
thebne
materi+a (l 0x. m2o bili= tscyo)r e
This assoutmheestr,h inbgesi negq uatlh,a itti sw ortghi viunpga pawni f
one'mso biliisti yn creabsyef di vmeo verse latitvhea ottfo on e'ospponentT.h e
coefficiiennt thses corinfgu ncti(oen. gt.h e0 .2 tihnea boveex amplaer)e
normala1ryr ivaetd bhoyp efuiln1tye llgiugeesnstw ofulr1k0 webdy m odifications
whicahr em adein the ligohftt hem anneirn w hicthh per ograpml ayThsu.s ,a
prograwmhi cht endteods acriflfiacger anwthleyna ttackiitnospg po netn'ksi ng
woulhda viet "sk inagt taccko"e ffirceideuncte d.
The structcurreea tbeyd p ar ograwmhe ni ti sl ookianhge aidsc al1ae dt ree. A
simptlree iess howinn t hef ollowdiinagg ram.
2
INTRODUCTION
p" (S,,P.) (. .S . )
P represIehnept oss ition wfhriocmth hper ogram ha1'> 0 maak em ovPeI.P' l ,
Ple,t .c• a ret hepo sitions Ihat.:anr cbaec hheydm akingo ncm m'e( MIM•2 • Ml•
etc.r,e spec:thf'roeml Py.) I'll. PeIH1.•:. a rPe lI]h'ep ositoinsI hacta nh �
reachaefdt etrh ep rogram m.aketshe moveM 1( top osiito nP Ia)n d itsp poonent
replwiietsth h meo veMsl lM•u .M u,e tc(.r espectively).
Fort hes akoef t hiesx planatwieos nh.a alsls umteh atth per ograanma lyzes
onltyo a deptho ft wo" ply("o hra lf-movTehsepol s.i tionPsI Ip,u •e t.c• a re
thutsh tee mrinapols itioannsdi ti sf orth e:o;pocs itiIonhast t hes corifnugn ction
musmt akei tesv aluatiThoens sc.o raesssoc iatde wit h PPInI.e• t .c• a rede noted
hyS 11S.1 2' Weet sC'h.a aldlo ptt hceo m-entIihaatan h igh(po sitiv)es corei sg ood
[ort hep rograamn dt haat l ow\ negatisvceo)ri es b'oofdo irt s opponTehnetni. f
Ihep rogram wteorm ea keI hem oveM s. lea10d i\Xn'g� itionI hPebI e.s tlha t its
opponencto ulddo wouhletod movet ow hichevoefrP II• PI1l1le.ll •.c .h adt he
lowest:l coracs sociatweidt hi t.T hu�I hes coreS Ia ssociatweidtpo hs itiPoIn
sholudb et hem inimuomf S ll' SSIIleZ't' c (.s imairyll fozr.S ]Se>t c.S)i.n cteh e
prograwmi shetsom aximi/i.tes oscwonr esihto umlodv et ow hicheovfeP rI P.z ,
1'), thhaehs i ghesst� '{)asrseo ciatw�idt hit .T hisp rocesosf c hoosintgh e
maximuomf t hem inimums oft hmea ximumosf t hmei nimumosf• . .i sc alled
theM INIMAXm ethodM.i nimawxa so riginaadlvloyc atbeySd h annoann d
todayc'hse spsr ograumss ea sophisticmaotdeidf icaotfim oinn im.a x(One
obviomuosd ificaitsti hoannt o t all borfat nhceth reeaser aen alyztoet dh se ame
depth-oinfe l inaep peatrosl osteh eq ueefno nr othintgh,ea nn alyosfit sh at
liniesi mmedtiealcyur tailwehde.r eaa sl ongse quenocfee xchangmeaysb e
3
1975U .S.C OMPUTER CHESSC HAMPIONSHIP
analyzteoad d eptohf tepnl oyrm ore).
SincSeh annont'ism ea muchf astmeert hodo ft ree·sheairncgh asb een
discovertehde,s o-calalplehda -beatlag oritThhmi.s a lgoritfhimn dtsh e
minimasxo lut(i.oient. h es amemo ve asw oulbde f ounedm ployitnhgem inimax
methodb)u tit doesso a fteexra minionngla yv ersym alplr oportioonft hen odes
ont het reTeh.i iss m adepo ssibblyec uttionfgfs ubstantpioarlt ioonfts h et ree
usinag s implleo,g icaarlgm uent-Iaf move canb er efutiendo new ayt hen
theriesn on eetdo s ee iitcf a na lsboe r eufteidn a nyo thewra ys incieti sa lready
obviotuhsa tth emo ve shoulndo tb e playTehdea. l pha-baeltgao riitshn mo wi n
usei nv irtuaallcllh ye spsr ograms.
A BrieHfis toorfyCh ess Programming
Shannon's papwerri twtaines n1 948a ndp ublishien1d 9 50.H e did not
descirbea na ctucahles sp rogramb uth ed ids uggemsatn yu sefiudle awsh ich
arest ilinl us.eH e realiztehde n ecessoift yh avai gnogo ds corifnugn cti(oan
chesmsa sterm'oss tv aluabalsesei tsh i asb iltiotay s sestsh eme rito fa p osition).
He alspooi nteodu tt haat scorifnugn ctiwoonu ldbe u seleins ts hee ndgame
wherea differaepnptr oaicshr equiraendd t haitt c oulodn lyb ea ppliine d
quiesceponsti tion(s1.ist wr onge valuatiponsgi taiw ohne ryeo uare a rodookwn
asl ositfi tis youtru rtno mo ve andy ouc anr ecapett uher rookat o nce.)
In1 957a,g rouapt t heLo s Alamossc ientriesfeaircc hes tabslhimen(ta lso the
scenoefw orko nt hea tomibco mbw) rotaep rogratmop lacyh esso na s ix-by-six
boardo,m ittitnhgeb ishopTsh.ep urposoef t hewiorr kw ast oi nvestigate some
oft hed ifficuolfct hieesspsro graminbgu.tu nforttuenlatyh eriers ulint nso w ay
contribauntyetdh ing.
Thef irsptr ogarmt haptl ayepdr opecrh essw asw ritteantM ITi nt hem id-late
1950'bsy AJ ex Bernsteainnd o thersT.h eiprr ograwmo rkebdy c hoositnhge
apparenbtelsyst e vemno vesa,n alyztihneg best rseepvleitneh se.b esste ven
replitesot heser epilesa,n dt heb ests evne relpietsot hesTehe. deptohf t heir
trewea st hufsi xeadtf ouprl ya ndt hen umbeorft erminpaosli tioenvsa luabtye d
their progrwaams 74. or 2,401.T he program moveda t intervoafl s
apprxoimateeliyg hmti nuteIstp. l ayeldi kae b eginnebru ta ttractmeudc hm ore
publicitiyn theU nitedS tatetsh and idt heB otivnniSkm-ysloWvo rld
Championsmhaitpc htesh awte reb einpgl ayeadta boutth atti m.e
In1 962AJ,a n Kotoka,nM IT undergraduawtreo.t ec hae spsr ografmo rh is
batcheltohre'ssi Ast. t he tiimtwe a sw rittKeont okp'rso graaml mostw ent
unntoicebdu,tf ivyee arlsa tietrw asu seads t heb asiosft heS tanforUdn iversity
programt haptl ayeafd ou-rgammaet chw itahp rografmr omM oscow.
TheS oviperto grawmo nt wog ames andt heo thetrw ow erea greeddr awn,
event hougthh eS oviperto grasmt oodb ettienrb oth drgaawmnes .T hiwsa st he
firstti met hatS ovieetf foritnst hef ielodf c omputecrh essw erew idely