chess-The Oxford Companion to Chess - First Edition by David Hooper & Kenneth Whyld

350 THEMATICVARI,A'IION
defe.ted bv only one black rcp1r. (For some
exanples sec R.Fr rx
E. ihe problen by
u1!rEunderBLoc(. andlheprobleB byR.rrNunder
TITEtrIATIC VARIAIION. one ollhe nain varia
tionsthat reveals rhe problen conposels idea- as
dhiincr lron By pLAy. Forexamplc, inthe probten
given under Nrcsr wn.D. ihcre are eight thenatic
vdn.dons (each a diffcrenl oove ol the black
knigho, and allother varialions are by pliy.
'IEDME. The thene of a problen lor studyl
consnts ol thc liDc or lines oi play {hich were
upp.rmost in the composer'snidd whcn nc madc
thc problcm [or study] and which presumablywiu
chieny inrerest tbe sollef-A. C. wHrE, Ir?
Good companion Two-nowr (192). other and
subordnratc lines ol play are like\r 10 be prescnti
rhcsludycomplserc IsthesesrDtrvARrAro\s. the
problemisl 8r-Pur. There are numerous wel
knowd thenes and their use in onginal seltings
need not invotve plagiarism.
TEEMD TOURNDY, a tourney lbi which conpos
esarerequired toshowaDarticularthcmcor idea.
TEEORY, a word with seleral chess connotatio$.
Plxyeis connonly speah olopenings rheory
al$ough opcnine variations have arisen empirically
and arc not evaluated co.sistently over a penod
oftineiin thh sense theoryneans tbeconsensus,
broadl, represented by cufenr literature on the
subieo. So callcd en4ame theory consisrs oI
inlormation aboul the basic endganei lrue stale
ments nay be nade regarding many spccilic
posnions or positions oI a similar type, but lhere
nre leN gencralizations of univeBal applicalioD.
'Ihcre h a well accepted theoiy, atlribuled 10
srErrnz, as to how rbegane should beconductcd.
This'geleral theory' begins with thcprcmisc that a