四月己巳，城濮。前一天，晋侯与宋公、齐国归父、崔夭、秦小子憖刚在这里会合；楚军背对着酅地扎营。开战之前，晋侯登上有莘的废墟看自己的队伍，说了一句：「少长有礼，其可用也！」——《左传》在这一天之前还记了一笔：晋车七百乘，韅、靷、鞅、靽。就在几天前，这支军队刚往后退了九十里。
退避三舍
退三舍的承诺，是几年前在楚国许下的。重耳流亡到楚，楚子问他：「公子若反晋国，则何以报不穀？」他答：子女玉帛、羽毛齿革，楚国都有；「若以君之灵，得反晋国，晋楚治兵，遇于中原，其辟君三舍。若不获命，其左执鞭弭，右属櫜鞬，以与君周旋。」——若托您的福回到晋国，将来晋楚交战、在中原相遇，我退您三舍；若还得不到谅解，那就左手执鞭弭、右肩挂弓囊，跟您周旋。当时子玉要杀他，楚子没答应。
二十八年，这话要兑现了。楚王本来不想打：他命子玉撤围宋之兵，说「无从晋师」，还引《军志》三句——「允当则归」「知难而退」「有德不可敌」——说这三句说的就是晋国。子玉使伯棼请战，王怒，「少与之师，唯西广、东宫与若敖之六卒实从之」。子玉使宛春告晋：「请复卫侯而封曹，臣亦释宋之围。」先轸出主意：私下许曹、卫复国以离间，执宛春以激怒楚，「既战而后图之」。曹、卫果然告绝于楚；子玉怒，从晋师；晋师退。军吏说：「以君辟臣，辱也。且楚师老矣，何故退？」子犯答：「师直为壮，曲为老，岂在久乎？微楚之惠不及此，退三舍辟之，所以报也。背惠食言，以亢其雠，我曲楚直……若其不还，君退臣犯，曲在彼矣。」——退三舍，楚众欲止，子玉不可。三十里为一舍，三舍九十里，这是通行说法，两页都没有注。
城濮的阵
到了城濮，气氛更紧。楚师背酅而舍，晋侯患之；舆人诵「原田每每，舍其旧而新是谋」，他听了反而起疑；子犯说「战也」，栾贞子说「汉阳诸姬，楚实尽之。思小惠而忘大耻，不如战也」。晋侯梦见与楚子搏斗，楚子伏在他身上吮他的脑，他害怕；子犯解梦说「吉！我得天，楚伏其罪，吾且柔之矣」。接着是两段辞令：子玉使斗勃请战，说「请与君之士戏，君冯轼而观之，得臣与寓目焉」；晋侯使栾枝对答：「寡君闻命矣。楚君之惠，未之敢忘，是以在此。为大夫退，其敢当君乎？既不获命矣，敢烦大夫谓二三子：『戒尔车乘，敬尔君事，诘朝将见。』」——明天早上见。
阵形分得清楚。晋：中军由先轸（原轸）将，郤溱佐；上军狐毛、狐偃；下军栾枝、胥臣。楚：子玉以若敖之六卒将中军，说「今日必无晋矣」；子西将左，子上将右。晋车七百乘，楚军这边，《左传》只记了王所给的那一点——西广、东宫与若敖之六卒，没有给总数。
己巳那一天
开合只有几步。晋师陈于莘北，胥臣以下军之佐当陈、蔡；「胥臣蒙马以虎皮，先犯陈、蔡。陈、蔡奔，楚右师溃。」接着是两记假动作：「狐毛设二旆而退之」；「栾枝使舆曳柴而伪遁」——车后拖柴扬起尘土，装出逃跑的样子；「楚师驰之」，追了过来。然后「原轸、郤溱以中军公族横击之」；「狐毛、狐偃以上军夹攻子西，楚左师溃。楚师败绩」。只有子玉「收其卒而止，故不败」。
战后也有账：晋师「三日馆谷」，到癸酉才还；甲午到衡雍，在践土作王宫；五月献楚俘，「驷介百乘，徒兵千」；王策命晋侯为侯伯，赐「大辂之服，戎辂之服，彤弓一，彤矢百，玈弓矢千，秬鬯一卣，虎贲三百人」，命辞是「敬服王命，以绥四国，纠逖王慝」。子玉的结局，两页说法不同：《春秋》经文只写「楚杀其大夫得臣」；《史记·晋世家》说楚成王「怒其不用其言，贪与晋战，让责子玉，子玉自杀」。
两页之间
数字与说法要分层并录，不能合成一套。兵力：《左传》给晋「七百乘」，楚只给「西广、东宫与若敖之六卒」；《史记·晋世家》不载晋车数，只说「己巳，与楚兵合战，楚兵败」——两页不合，不裁断，也不把乘数换算成人数。别的异文也一样：《左传》数曹伯之罪，是「不用僖负羁而乘轩者三百人」；《史记》作「不用釐负羁言，而用美女乘轩者三百人」。《史记》还多一句「晋焚楚军，火数日不息」，以及文公战后行赏的一段——以狐偃「说我毋失信」为万世之功，先轸「军事胜为右」为一时之说。这些都不见于《左传》这一段。
「退避三舍」也可以读到两层。《左传》里它先是子犯算的直曲账：退，是为了报楚惠；楚若不还，「君退臣犯，曲在彼矣」。《史记》里它变成文公口中的「昔在楚，约退三舍，可倍乎」，又变成战后行赏的理由。两页各给一层，本篇并列，不裁断哪一层才是本意，更不把它引申成「诚信」「仁义」的教材；三十里一舍、九十里，只是照原文与通行说法写下来。
一天的战事
这篇只写这一天：地点城濮，时间四月己巳，晋车七百乘，楚的中军、左军、右军，退三舍的理由，开战的四步与结果。两页都没有给地图、没有给战场面积、没有给双方总兵力；本篇也不补地图、不补考古。《左传》自己在僖公二十七年末尾有一句评语「一战而霸，文之教也」——那是《左传》的话，可以引，但不当作「晋楚争霸转折点」的史论来发挥。
参考来源与延伸阅读
- 《春秋左氏传》僖公（维基文库本，未与点校本复核） — The full account. The promise in the twenty-third year: 'if by your spirit I return to Jin, and Jin and Chu marshal their armies and meet on the central plain, I will retire three she before you; if I still do not receive your command, then with whip and bow in my left hand and quiver at my right I will have a turn with you' (其辟君三舍……以与君周旋). In the twenty-eighth year: the king of Chu orders Zi Yu not to follow the Jin army and quotes the Military Records; 'he gave him few troops: only the Western Broad, the Eastern Palace and the six companies of Ruo Ao went with him' (唯西广、东宫与若敖之六卒实从之); Wan Chun's proposal and Xian Zhen's counter; the retreat, the officers' objection, and Zi Fan's 'an army is strong when it is straight and old when it is crooked … a lord has retired and a subject has pressed on him, and the crookedness is theirs' (师直为壮，曲为老……君退臣犯，曲在彼矣). At Chengpu: the divination songs, the dream, the two speeches (请与君之士戏……诘朝将见), 'seven hundred chariots of Jin' (晋车七百乘), the lines under Xian Zhen, Hu Mao and Hu Yan, Luan Zhi and Xu Chen, and Zi Yu's centre with Zi Xi left and Zi Shang right; the fighting — tiger skins, two pennants, brushwood dust, 'Yuan Zhen and Xi Zhen with the ducal clan struck across' (原轸、郤溱以中军公族横击之), both Chu wings broken, Zi Yu gathering his men; then three days of Chu's grain, the presentation of prisoners, and the king's charge and gifts. The Chun Qiu text in the same page has 'Chu killed its grand officer Dechen'.
- 《史记》卷三十九·晋世家（西汉司马迁；维基文库本，未与点校本复核） — The parallel account with the differences that matter. The same campaign, with 'three hundred beauties riding in carriages' (用美女乘轩者三百人也) where the Zuo Zhuan has only the three hundred riders; the king of Chu's refusal to fight and his 'few troops'; Wan Chun's mission and Xian Zhen's counter; the retreat justified in the lord of Jin's own words, 'in Chu I promised to retire three she; can I double it?' (昔在楚，约退三舍，可倍乎). The battle is given in one line, with no chariot count: 'on ji-si he joined battle with the Chu army, and the Chu army was defeated' (己巳，与楚兵合战，楚兵败). Then the presentation of prisoners, the king's appointment of the lord of Jin as leader of the lords with the gifts, and the line 'Jin burned the Chu army, and the fire did not go out for several days' (晋焚楚军，火数日不息). Zi Yu's end: the king 'reproached Zi Yu, and Zi Yu killed himself' (让责子玉，子玉自杀). After the battle the lord of Jin ranks the rewards, putting Hu Yan first because 'he told me not to break faith', over Xian Zhen's 'in war victory is the rule' — a judgement the Zuo Zhuan passage does not contain.
