English translation
Sun Tzu said: To govern many as if governing few — that is a matter of division and numbers. To fight many as if fighting few — that concerns form and designation. To marshal an army so that it will certainly engage the enemy without defeat — that lies in the use of orthodox and unorthodox tactics. Where force is applied, as when hurling a heavy stone at an egg, that concerns emptiness and solidity.
Chinese source
孫子曰：凡治衆如治寡，分數是也；鬥衆如鬥寡，形名是也；三軍之衆，可使必受敵而無敗者，奇正是也；兵之所加，如以碫投卵者，虛實是也。
In all fighting, match with the orthodox and win by the unorthodox. Therefore the skillful user of surprise is inexhaustible like Heaven and Earth, unending like rivers and seas. They end only to begin again, like the sun and moon; they die and are reborn, like the four seasons. Sounds are not more than five, yet the changes of the five sounds cannot be fully heard; colors are not more than five, yet the variations of five colors cannot be fully seen; tastes are not more than five, yet the shifts of five tastes cannot be fully sampled. Battle formations are no more than orthodox and unorthodox, yet the variations of orthodox and unorthodox cannot be exhausted. Orthodox and unorthodox generate one another in a cycle without end — who can fully fathom it?
Chinese source
凡戰者，以正合，以奇勝。故善出奇者，無窮如天地，不竭如江海。終而復始，日月是也。死而復生，四時是也。聲不過五，五聲之變，不可勝聽也；色不過五，五色之變，不可勝觀也；味不過五，五味之變，不可勝嘗也；戰勢不過奇正，奇正之變，不可勝窮也。奇正相生，如循環之無端，孰能窮之哉？
The swiftness of rushing water that can carry off a floating stone — that is momentum. The rapid strike of a bird of prey that can break and shatter — that is tempo. Therefore the skillful fighter’s momentum is steep, and his tempo is brief. Momentum is like a drawn crossbow; tempo is like the release mechanism.
Chinese source
激水之疾，至於漂石者，勢也；鷙鳥之疾，至於毀折者，節也。故善戰者，其勢險，其節短。勢如彍弩，節如發機。
Confused and clamorous, the contest appears chaotic yet cannot be thrown into disorder; blurred and indeterminate, the formation is rounded and cannot be broken. Disorder is born of order; timidity is born of courage; weakness is born of strength. Order and disorder are matters of organization and numbers; courage and timidity are matters of momentum; strength and weakness are matters of form.
Chinese source
紛紛紜紜，鬥亂而不可亂也；渾渾沌沌，形圓而不可敗也。亂生於治，怯生於勇，弱生於強。治亂，數也；勇怯，勢也；強弱，形也。
Therefore the one who skillfully moves the enemy shapes a situation to which the enemy will respond; he offers and the enemy will take. Use advantage to move them, and await them with your troops.
Chinese source
故善動敵者，形之，敵必從之；予之，敵必取之。以利動之，以卒待之。
Thus the skilled commander seeks victory in the situation, not by blaming his men; therefore he can choose people and assign them to fit the situation. To rely on momentum is to fight with men as if turning logs and stones. The nature of wood and stone: when level they rest, when tilted they move; when square they stop, when round they roll. Therefore the skillful commander’s momentum is like rolling a round stone down a thousand‑footh cliff — that is momentum.
Chinese source
故善戰者，求之於勢，不責於人，故能擇人而任勢。任勢者，其戰人也，如轉木石。木石之性，安則靜，危則動，方則止，圓則行。故善戰人之勢，如轉圓石於千仞之山者，勢也。