you　know　yourself　but　not　the　enemy；　for　every　victory　gained　you
  will　also　suffer　a　defeat。
  ＇Li　Ch‘uan　cites　the　case　of　Fu　Chien；　prince　of　Ch‘in；　　who
  in　383　A。D。　marched　with　a　vast　army　against　the　Chin　Emperor。
  When　warned　not　to　despise　an　enemy　who　could　command　the
  services　of　such　men　as　Hsieh　An　and　Huan　Ch‘ung；　he　boastfully
  replied：　　　〃I　have　the　population　of　eight　provinces　at　my　back；
  infantry　and　horsemen　to　the　number　of　one　million；　　why；　　they
  could　dam　up　the　Yangtsze　River　itself　by　merely　throwing　their
  whips　　　into　　　the　stream。　　What　danger　have　I　　　to　　　fear？〃
  Nevertheless；　　his　forces　were　soon　after　disastrously　routed　at
  the　Fei　River；　and　he　was　obliged　to　beat　a　hasty　retreat。＇
  If　you　know　neither　the　enemy　nor　yourself；　you　will　succumb　in
  every　battle。
  ＇Chang　Yu　said：　　〃Knowing　the　enemy　enables　you　to　take　the
  offensive；　　　knowing　yourself　enables　you　to　stand　on　　　the
  defensive。〃　　He　adds：　　〃Attack　is　the　secret　of　defense；　　defense
  is　the　planning　of　an　attack。〃　　It　would　be　hard　to　find　a　better
  epitome　of　the　root…principle　of　war。＇
  …
  IV。　　TACTICAL　DISPOSITIONS
  ＇Ts‘ao　Kung　explains　the　Chinese　meaning　of　the　words　for
  the　title　of　this　chapter：　　〃marching　and　countermarching　on　the
  part　of　the　two　armies　with　a　view　to　discovering　each　other's
  condition。〃　　　Tu　Mu　says：　　〃It　is　through　the　dispositions　of　an
  army　that　its　condition　may　be　discovered。　　Conceal　　　your
  dispositions；　and　your　condition　will　remain　secret；　which　leads
  to　victory；；　　show　your　dispositions；　and　your　condition　will
  become　patent；　which　leads　to　defeat。〃　　Wang　Hsi　remarks　that　the
  good　general　can　〃secure　success　by　modifying　his　tactics　to　meet
  those　of　the　enemy。〃＇
  1。　　Sun　Tzu　said：　　The　good　fighters　of　old　first　put
  themselves　beyond　the　possibility　of　defeat；　and　then　waited　for
  an　opportunity　of　defeating　the　enemy。
  2。　　To　secure　ourselves　against　defeat　lies　in　our　own
  hands；　but　the　opportunity　of　defeating　the　enemy　is　provided　by
  the　enemy　himself。
  ＇That　is；　of　course；　by　a　mistake　on　the　enemy's　part。＇
  3。　　Thus　the　good　fighter　is　able　to　secure　himself　against
  defeat；
  ＇Chang　Yu　says　this　is　done；　　〃By　concealing　the　disposition
  of　his　troops；　covering　up　his　tracks；　and　taking　unremitting
  precautions。〃＇
  but　cannot　make　certain　of　defeating　the　enemy。
  4。　　Hence　the　saying：　　One　may　KNOW　how　to　conquer　without
  being　able　to　DO　it。
  5。　　Security　against　defeat　implies　defensive　tactics；
  ability　to　defeat　the　enemy　means　taking　the　offensive。
  ＇I　retain　the　sense　found　in　a　similar　passage　in　ss。　　1…3；
  in　spite　of　the　fact　that　the　commentators　are　all　against　me。
  The　meaning　they　give；　　〃He　who　cannot　conquer　takes　　　the
  defensive；〃　is　plausible　enough。＇
  6。　　　Standing　on　the　defensive　indicates　　　insufficient
  strength；　attacking；　a　superabundance　of　strength。
  7。　　The　general　who　is　skilled　in　defense　hides　in　the　most
  secret　recesses　of　the　earth；
  ＇Literally；　　〃hides　under　the　ninth　earth；〃　　which　is　a
  metaphor　indicating　the　utmost　secrecy　and　concealment；　so　that
  the　enemy　may　not　know　his　whereabouts。〃＇
  he　who　is　skilled　in　attack　flashes　forth　from　the　topmost
  heights　of　heaven。
  ＇Another　metaphor；　implying　that　he　falls　on　his　adversary
  like　a　thunderbolt；　against　which　there　is　no　time　to　prepare。
  This　is　the　opinion　of　most　of　the　commentators。＇
  Thus　on　the　one　hand　we　have　ability　to　protect　ourselves；　on　the
  other；　a　victory　that　is　complete。
  8。　　To　see　victory　only　when　it　is　within　the　ken　of　the
  common　herd　is　not　the　acme　of　excellence。
  ＇As　Ts‘ao　Kung　remarks；　〃the　thing　is　to　see　the　plant
  before　it　has　germinated；〃　to　foresee　the　event　before　the　action
  has　begun。　　Li　Ch‘uan　alludes　to　the　story　of　Han　Hsin　who；　　when
  about　to　attack　the　vastly　superior　army　of　Chao；　　which　was
  strongly　entrenched　in　the　city　of　Ch‘eng…an；　　said　to　his
  officers：　　〃Gentlemen；　we　are　going　to　annihilate　the　enemy；　　and
  shall　meet　again　at　dinner。〃　　The　officers　hardly　took　his　words
  seriously；　　and　gave　a　very　dubious　assent。　　But　Han　Hsin　had
  already　worked　out　in　his　mind　the　details　of　a　clever　stratagem；
  whereby；　　as　he　foresaw；　he　was　able　to　capture　the　city　and
  inflict　a　crushing　defeat　on　his　adversary。〃＇
  9。　　Neither　is　it　the　acme　of　excellence　if　you　fight　and
  conquer　and　the　whole　Empire　says；　〃Well　done！〃
  ＇True　excellence　being；　as　Tu　Mu　says：　　〃To　plan　secretly；
  to　move　surreptitiously；　to　foil　the　enemy's　intentions　and　balk
  his　schemes；　so　that　at　last　the　day　may　be　won　without　shedding
  a　drop　of　blood。〃　　Sun　Tzu　reserves　his　approbation　for　things
  that
  〃the　world's　coarse　thumb
  And　finger　fail　to　plumb。〃＇
  10。　　To　lift　an　autumn　hair　is　no　sign　of　great　strength；
  ＇〃Autumn〃　hair〃　is　explained　as　the　fur　of　a　hare；　which　is
  finest　in　autumn；　when　it　begins　to　grow　afresh。　　The　phrase　is　a
  very　common　one　in　Chinese　writers。＇
  to　see　the　sun　and　moon　is　no　sign　of　sharp　sight；　to　hear　the
  noise　of　thunder　is　no　sign　of　a　quick　ear。
  ＇Ho　Shih　gives　as　real　instances　of　strength；　　sharp　sight
  and　quick　hearing：　　Wu　Huo；　who　could　lift　a　tripod　weighing　250
  stone；　　Li　Chu；　who　at　a　distance　of　a　hundred　paces　could　see
  objects　no　bigger　than　a　mustard　seed；　and　Shih　K‘uang；　a　blind
  musician　who　could　hear　the　footsteps　of　a　mosquito。＇
  11。　　What　the　ancients　called　a　clever　fighter　is　one　who
  not　only　wins；　but　excels　in　winning　with　ease。
  ＇The　last　half　is　literally　〃one　who；　conquering；　excels　in
  easy　conquering。〃　　　Mei　Yao…ch‘en　says：　　〃He　who　only　sees　the
  obvious；　wins　his　battles　with　difficulty；　he　who　looks　below　the
  surface　of　things；　wins　with　ease。〃＇
  12。　　Hence　his　victories　bring　him　neither　reputation　for
  wisdom　nor　credit　for　courage。
  ＇Tu　Mu　explains　this　very　well：　　〃Inasmuch　as　his　victories
  are　gained　over　circumstances　that　have　not　come　to　light；　　the
  world　as　large　knows　nothing　of　them；　and　he　wins　no　reputation
  for　wisdom；　inasmuch　as　the　hostile　state　submits　before　there
  has　been　any　bloodshed；　he　receives　no　credit　for　courage。〃＇
  13。　　He　wins　his　battles　by　making　no　mistakes。
  ＇Ch‘en　Hao　says：　　　〃He　plans　no　superfluous　marches；　　he
  devises　no　futile　attacks。〃　　The　connection　of　ideas　is　thus
  explained　by　Chang　Yu：　　〃One　who　seeks　to　conquer　by　sheer
  strength；　clever　though　he　may　be　at　winning　pitched　battles；　　is
  also　liable　on　occasion　to　be　vanquished；　whereas　he　who　can　look
  into　the　future　and　discern　conditions　that　are　not　yet　manifest；
  will　never　make　a　blunder　and　therefore　invariably　win。〃＇
  Making　no　mistakes　is　what　establishes　the　certainty　of　victory；
  for　it　means　conquering　an　enemy　that　is　already　defeated。
  14。　　Hence　the　skillful　fighter　puts　himself　into　a　position
  which　makes　defeat　impossible；　and　does　not　miss　the　moment　for
  defeating　the　enemy。
  ＇A　　〃counsel　of　perfection〃　　as　Tu　Mu　truly　　　observes。
  〃Position〃　need　not　be　confined　to　the　actual　ground　occupied　by
  the　troops。　　It　includes　all　the　arrangements　and　preparations
  which　a　wise　general　will　make　to　increase　the　safety　of　his
  army。＇
  15。　　Thus　it　is　that　in　war　the　victorious　strategist　only
  seeks　battle　after　the　victory　has　been　won；　whereas　he　who　is
  destined　to　defeat　first　fights　and　afterwards　looks　for　victory。
  ＇Ho　Shih　thus　expounds　the　paradox：　　〃In　warfare；　first　lay
  plans　which　will　ensure　victory；　and　then　lead　your　army　to
  battle；　　if　you　will　not　begin　with　stratagem　but　rely　on　brute
  strength　alone；　victory　will　no　longer　be　assured。〃＇
  16。　　The　consummate　leader　cultivates　the　moral　law；　　and
  strictly　adheres　to　method　and　discipline；　thus　it　is　in　his
  power　to　control　success。
  17。　　In　respect　of　military　method；　　we　have；　　firstly；
  Measurement；　　　secondly；　　　Estimation　　　of　　　quantity；　　　thirdly；
  Calculation；　fourthly；　Balancing　of　chances；　fifthly；　Victory。
  18。　　Measurement　owes　its　existence　to　Earth；　Estimation　of
  quantity　to　Measurement；　Calculation　to　Estimation　of　quantity；
  Balancing　of　chances　to　Calculation；　and　Victory　to　Balancing　of
  chances。
  ＇It　is　not　easy　to　distinguish　the　four　terms　very　clearly
  in　the　Chinese。　　The　first　seems　to　be　surveying　and　measurement
  of　the　ground；　which　enable　us　to　form　an　estimate　of　the　enemy's
  strength；　　and　to　make　calculations　based　on　the　data　thus
  obtained；　we　are　thus　led　to　a　general　weighing…up；　or　comparison
  of　the　enemy's　chances　with　our　own；　if　the　latter　turn　the
  scale；　　then　victory　ensues。　　The　chief　difficulty　lies　in　thi