37。　　By　altering　his　arrangements　and　changing　his　plans；
  ＇Wang　Hsi　thinks　that　this　means　not　using　the　same
  stratagem　twice。＇
  he　keeps　the　enemy　without　definite　knowledge。
  ＇Chang　Yu；　　in　a　quotation　from　another　work；　　says：　　　〃The
  axiom；　　that　war　is　based　on　deception；　does　not　apply　only　to
  deception　of　the　enemy。　　You　must　deceive　even　your　own　soldiers。
  Make　them　follow　you；　but　without　letting　them　know　why。〃＇
  By　shifting　his　camp　and　taking　circuitous　routes；　　he　prevents
  the　enemy　from　anticipating　his　purpose。
  38。　　At　the　critical　moment；　the　leader　of　an　army　acts　like
  one　who　has　climbed　up　a　height　and　then　kicks　away　the　ladder
  behind　him。　　He　carries　his　men　deep　into　hostile　territory
  before　he　shows　his　hand。
  ＇Literally；　〃releases　the　spring〃　（see　V。　ss。　15）；　that　is；
  takes　some　decisive　step　which　makes　it　impossible　for　the　army
  to　returnlike　Hsiang　Yu；　who　sunk　his　ships　after　crossing　a
  river。　　Ch‘en　Hao；　followed　by　Chia　Lin；　understands　the　words
  less　well　as　〃puts　forth　every　artifice　at　his　command。〃＇
  39。　　He　burns　his　boats　and　breaks　his　cooking…pots；　like　a
  shepherd　driving　a　flock　of　sheep；　he　drives　his　men　this　way　and
  that；　and　nothing　knows　whither　he　is　going。
  ＇Tu　Mu　says：　　　〃The　army　is　only　cognizant　of　orders　to
  advance　or　retreat；　　it　is　ignorant　of　the　ulterior　ends　of
  attacking　and　conquering。〃＇
  40。　　To　muster　his　host　and　bring　it　into　danger：this　may
  be　termed　the　business　of　the　general。
  ＇Sun　Tzu　means　that　after　mobilization　there　should　be　no
  delay　in　aiming　a　blow　at　the　enemy's　heart。　　Note　how　he　returns
  again　and　again　to　this　point。　　Among　the　warring　states　of
  ancient　China；　desertion　was　no　doubt　a　much　more　present　fear
  and　serious　evil　than　it　is　in　the　armies　of　today。＇
  41。　　The　different　measures　suited　to　the　nine　varieties　of
  ground；
  ＇Chang　Yu　says：　　〃One　must　not　be　hide…bound　in　interpreting
  the　rules　for　the　nine　varieties　of　ground。＇
  the　expediency　of　aggressive　or　defensive　tactics；　　and　the
  fundamental　laws　of　human　nature：　　these　are　things　that　must
  most　certainly　be　studied。
  42。　　When　invading　hostile　territory；　the　general　principle
  is；　　that　penetrating　deeply　brings　cohesion；　penetrating　but　a
  short　way　means　dispersion。
  ＇Cf。　supra；　ss。　20。＇
  43。　　When　you　leave　your　own　country　behind；　and　take　your
  army　across　neighborhood　territory；　you　find　yourself　on　critical
  ground。
  ＇This　〃ground〃　is　curiously　mentioned　in　VIII。　ss。　2；　but　it
  does　not　figure　among　the　Nine　Situations　or　the　Six　Calamities
  in　chap。　X。　　One's　first　impulse　would　be　to　translate　it　distant
  ground；〃　but　this；　if　we　can　trust　the　commentators；　is　precisely
  what　is　not　meant　here。　　Mei　Yao…ch‘en　says　it　is　〃a　position　not
  far　enough　advanced　to　be　called　'facile；'　and　not　near　enough　to
  home　to　be　'dispersive；'　but　something　between　the　two。〃　　Wang　Hsi
  says：　　〃It　is　ground　separated　from　home　by　an　interjacent　state；
  whose　territory　we　have　had　to　cross　in　order　to　reach　it。
  Hence；　　it　is　incumbent　on　us　to　settle　our　business　there
  quickly。〃　　　He　adds　that　this　position　is　of　rare　occurrence；
  which　is　the　reason　why　it　is　not　included　among　the　Nine
  Situations。＇
  When　there　are　means　of　communication　on　all　four　sides；　　the
  ground　is　one　of　intersecting　highways。
  44。　　When　you　penetrate　deeply　into　a　country；　it　is　serious
  ground。　　When　you　penetrate　but　a　little　way；　　it　is　facile
  ground。
  45。　　When　you　have　the　enemy's　strongholds　on　your　rear；　and
  narrow　passes　in　front；　it　is　hemmed…in　ground。　　When　there　is　no
  place　of　refuge　at　all；　it　is　desperate　ground。
  46。　　Therefore；　on　dispersive　ground；　I　would　inspire　my　men
  with　unity　of　purpose。
  ＇This　end；　according　to　Tu　Mu；　is　best　attained　by　remaining
  on　the　defensive；　and　avoiding　battle。　　Cf。　supra；　ss。　11。＇
  On　facile　ground；　I　would　see　that　there　is　close　connection
  between　all　parts　of　my　army。
  ＇As　Tu　Mu　says；　the　object　is　to　guard　against　two　possible
  contingencies：　　　〃（1）　　the　desertion　of　our　own　troops；　　（2）　　a
  sudden　attack　on　the　part　of　the　enemy。〃　　Cf。　VII。　ss。　17。　　Mei
  Yao…ch‘en　says：　　〃On　the　march；　the　regiments　should　be　in　close
  touch；　　in　an　encampment；　there　should　be　continuity　between　the
  fortifications。〃＇
  47。　　On　contentious　ground；　I　would　hurry　up　my　rear。
  ＇This　is　Ts‘ao　Kung's　interpretation。　　Chang　Yu　adopts　it；
  saying：　　　〃We　must　quickly　bring　up　our　rear；　so　that　head　and
  tail　may　both　reach　the　goal。〃　　That　is；　they　must　not　be　allowed
  to　straggle　up　a　long　way　apart。　　Mei　Yao…ch‘en　offers　another
  equally　plausible　explanation：　　〃Supposing　the　enemy　has　not　yet
  reached　the　coveted　position；　and　we　are　behind　him；　　we　should
  advance　with　all　speed　in　order　to　dispute　its　possession。〃
  Ch‘en　Hao；　　on　the　other　hand；　assuming　that　the　enemy　has　had
  time　to　select　his　own　ground；　quotes　VI。　ss。　1；　where　Sun　Tzu
  warns　us　against　coming　exhausted　to　the　attack。　　His　own　idea　of
  the　situation　is　rather　vaguely　expressed：　　　〃If　there　is　a
  favorable　position　lying　in　front　of　you；　detach　a　picked　body　of
  troops　to　occupy　it；　then　if　the　enemy；　relying　on　their　numbers；
  come　up　to　make　a　fight　for　it；　you　may　fall　quickly　on　their
  rear　with　your　main　body；　and　victory　will　be　assured。〃　　It　was
  thus；　　he　adds；　that　Chao　She　beat　the　army　of　Ch‘in。　　（See　p。
  57。）＇
  48。　　On　open　ground；　I　would　keep　a　vigilant　eye　on　my
  defenses。　　　On　　　ground　of　intersecting　highways；　　　I　　　would
  consolidate　my　alliances。
  49。　　On　serious　ground；　I　would　try　to　ensure　a　continuous
  stream　of　supplies。
  ＇The　commentators　take　this　as　referring　to　forage　and
  plunder；　　not；　as　one　might　expect；　to　an　unbroken　communication
  with　a　home　base。＇
  On　difficult　ground；　I　would　keep　pushing　on　along　the　road。
  50。　　On　hemmed…in　ground；　I　would　block　any　way　of　retreat。
  ＇Meng　Shih　says：　　〃To　make　it　seem　that　I　meant　to　defend
  the　position；　　whereas　my　real　intention　is　to　burst　suddenly
  through　the　enemy's　lines。〃　　Mei　Yao…ch‘en　says：　　〃in　order　to
  make　my　soldiers　fight　with　desperation。〃　　　Wang　Hsi　says；
  〃fearing　lest　my　men　be　tempted　to　run　away。〃　　Tu　Mu　points　out
  that　this　is　the　converse　of　VII。　ss。　36；　where　it　is　the　enemy
  who　is　surrounded。　　In　532　A。D。；　Kao　Huan；　afterwards　Emperor　and
  canonized　as　Shen…wu；　was　surrounded　by　a　great　army　under　Erh…
  chu　Chao　and　others。　　His　own　force　was　comparatively　small；
  consisting　only　of　2000　horse　and　something　under　30；000　foot。
  The　lines　of　investment　had　not　been　drawn　very　closely　together；
  gaps　being　left　at　certain　points。　　But　Kao　Huan；　　instead　of
  trying　to　escape；　　actually　made　a　shift　to　block　all　the
  remaining　outlets　himself　by　driving　into　them　a　number　of　oxen
  and　donkeys　roped　together。　　As　soon　as　his　officers　and　men　saw
  that　there　was　nothing　for　it　but　to　conquer　or　die；　　their
  spirits　rose　to　an　extraordinary　pitch　of　exaltation；　　and　they
  charged　with　such　desperate　ferocity　that　the　opposing　ranks
  broke　and　crumbled　under　their　onslaught。＇
  On　desperate　ground；　　I　would　proclaim　to　my　soldiers　the
  hopelessness　of　saving　their　lives。
  Tu　Yu　says：　　〃Burn　your　baggage　and　impedimenta；　throw　away
  your　stores　and　provisions；　choke　up　the　wells；　　destroy　your
  cooking…stoves；　　and　make　it　plain　to　your　men　that　they　cannot
  survive；　but　must　fight　to　the　death。〃　　Mei　Yao…ch‘en　says：　　〃The
  only　chance　of　life　lies　in　giving　up　all　hope　of　it。〃　　　This
  concludes　what　Sun　Tzu　has　to　say　about　　〃grounds〃　　and　the
  〃variations〃　corresponding　to　them。　　Reviewing　the　passages　which
  bear　on　this　important　subject；　we　cannot　fail　to　be　struck　by
  the　desultory　and　unmethodical　fashion　in　which　it　is　treated。
  Sun　Tzu　begins　abruptly　in　VIII。　ss。　2　to　enumerate　　〃variations〃
  before　touching　on　〃grounds〃　at　all；　but　only　mentions　five；
  namely　nos。　7；　5；　8　and　9　of　the　subsequent　list；　and　one　that　is
  not　included　in　it。　　A　few　varieties　of　ground　are　dealt　with　in
  the　earlier　portion　of　chap。　IX；　and　then　chap。　X　sets　forth　six
  new　grounds；　with　six　variations　of　plan　to　match。　　None　of　these
  is　　　mentioned　　　again；　　though　the　first　is　hardly　　　to　　　be
  distinguished　from　ground　no。　4　in　the　next　chapter。　　At　last；　in
  chap。　XI；　we　come　to　the　Nine　Grounds　par　excellence；　immediately
  followed　by　the　variations。　　This　takes　us　down　to　ss。　　14。　　In
  SS。　43…45；　fresh　definitions　are　provided　for　nos。　5；　6；　2；　8　and
  9　　（in　the　order　given）；　as　well　as　for　the　tenth　ground　noticed
  in　chap。　VIII；　and　finally；　the　nine　variations　are　enumerated
  once　more　from　beginning　to　end；　all；　with　the　exception　of　5；　　6
  and