Family background

Fa Zheng's ancestral home was in Mei County, Youfufeng Commandery, which is in present-day Mei County, Shaanxi. His ancestor was Tian Fazhang, who is historically known as King Xiang of the Qi state in the Warring States period. Tian Fazhang's descendants changed their family name from "Tian" to "Fa" after the fall of Qi in 221 BCE.

Fa Zheng's great-grandfather, Fa Xiong, served as the Administrator (太守) of Nan Commandery (南郡; around present-day Jingzhou, Hubei) during the reign of Emperor An in the Eastern Han dynasty. Fa Zheng's grandfather, Fa Zhen, was a reclusive scholar known for his lofty character; despite being a learned scholar, he led a humble life and repeatedly rejected offers to serve in the government. Fa Zheng's father, Fa Yan (法衍), whose courtesy name was Jimou (季謀), also served as a government official and held the positions of an assistant to the Excellency over the Masses (司徒) and the Minister of Justice (廷尉).

Service under Liu Zhang

In the early Jian'an era (196–220) of the reign of Emperor Xian, when famines broke out, Fa Zheng and his friend Meng Da travelled to Yi Province (covering present-day Sichuan and Chongqing) to join the provincial governor, Liu Zhang. Although Fa Zheng served as the Prefect (令) of Xindu County and later as a Colonel Who Advises the Army under Liu Zhang. Since he didn't have any connection to local clans and was defamed by other refugees from Youfufeng, who had also moved to Yi Province. He couldn't realize his ambitions. He maintained a close friendship with his colleague Zhang Song, who shared the same views as him about Liu Zhang being an incompetent and incapable governor.

In 208, Zhang Song travelled to Jing Province (covering present-day Hubei and Hunan) to meet the warlord Cao Cao, who controlled the Han central government and the figurehead Emperor Xian. After returning to Yi Province, Zhang Song advised Liu Zhang to break ties with Cao Cao and build friendly relations with another warlord, Liu Bei. When Zhang Song recommended Fa Zheng to be Liu Zhang's representative to meet Liu Bei, Fa initially refused to accept the task but eventually relented. When Fa Zheng returned from his mission, he told Zhang Song that Liu Bei had grand ambitions and persuaded Zhang to follow him to serve Liu Bei. They wanted to help him secure Yi province but did not have the occasion to do so.

Their opportunity came in 211, when Liu Zhang became fearful upon receiving news that Cao Cao was planning to attack the warlord Zhang Lu in Hanzhong Commandery. As Hanzhong Commandery was located strategically at the northern route leading into Yi Province, Liu Zhang would be in great peril if Hanzhong fell into Cao Cao's hands. Zhang Song proposed to Liu Zhang to invite Liu Bei to Yi Province to assist them in countering the threat posed by Cao Cao. Liu Zhang agreed and sent Fa Zheng as his envoy to contact Liu Bei. When Fa Zheng met Liu Bei, he secretly told him, "General, with your brilliance, you can overcome our incompetent and weak Governor Liu. Zhang Song, as a trusted adviser (of Liu Zhang), will serve as your spy. Upon acquiring Yi Province's wealth and resources, and having its natural barriers as protection, you can easily realise your grand ambitions." Fa Zheng also saw Liu Bei's marital problems and advised him to have Lady Sun sent back to Wu. Liu Bei accepted Fa Zheng's former advice and led his forces into Yi Province, where he met Liu Zhang at Fu County (涪縣; present-day Fucheng District, Mianyang, Sichuan). Liu Bei then led his troops north to Jiameng (葭萌; located about 20 km northeast of present-day Jiange County, Sichuan) before turning south to attack Liu Zhang later.

Helping Liu Bei seize Yi Province from Liu Zhang

Upon receiving news of Liu Bei's attack, Zheng Du, an assistant officer from Guanghan Commandery (廣漢郡; around present-day Guanghan, Sichuan) serving under Liu Zhang, pointed out to his lord that Liu Bei's army lacked supplies and was composed of newly recruited soldiers who might not be loyal to him. He suggested that Liu Zhang adopt a scorched earth policy against Liu Bei by forcing the residents of Baxi (巴西) and Zitong (梓潼) commanderies to relocate elsewhere and destroy all the granaries and supply depots in the commanderies, and then fortify their defences while avoiding direct conflict with Liu Bei. He claimed that if this strategy was implemented, Liu Bei would run out of supplies within 100 days and retreat, and then Liu Zhang could attack him while he was retreating. Liu Bei felt frustrated when he heard about Zheng Du's plan and consulted Fa Zheng about it. Fa Zheng predicted that Liu Zhang would not heed Zheng Du's suggestion and was proven right: In response to Zheng Du's plan, Liu Zhang not only rejected it on the grounds that it would cause disturbance to the people, but also dismissed Zheng from office.

In 214, when Liu Bei's army surrounded Luocheng (雒城), one of Liu Zhang's strongholds, Fa Zheng wrote a long letter to his former lord, pointing out that Liu Zhang was already in a highly disadvantageous position and urging him to give up resistance and surrender to Liu Bei.

Fa Zheng's letter was written as such:

Later that year, when Liu Bei's forces was besieging Yi Province's capital Chengdu, Xu Jing, a commandery Administrator serving under Liu Zhang, planned to surrender and defect to Liu Bei, but his plan was leaked out and hence aborted. Liu Zhang felt that he was already at the brink of destruction so he did not punish Xu Jing. He eventually surrendered and relinquished his control of Yi Province to Liu Bei. After taking over Yi Province, Liu Bei treated Xu Jing coldly because he felt that Xu was a disloyal person. Fa Zheng advised him, "Xu Jing is someone with an exaggerated reputation. However, my lord, you've recently built your foundation and you can't possibly explain the facts to everyone. Xu Jing's name is already well known throughout the Empire. If you don't treat him respectfully, others might think that you're belittling talented and virtuous people. You should honour and respect him, and make this known to everyone, just like how the King of Yan treated Guo Wei (郭隗)." Liu Bei followed Fa Zheng's advice and treated Xu Jing generously.

Sun Sheng criticizes Fa Zheng for his advice and the comparison between Guo Wei and Xu Jing :

Pei Songzhi completely disagrees with Sun Sheng's opinion:

Service under Liu Bei

Becoming Liu Beis Chief Adviser

Liu Bei appointed Fa Zheng as the Administrator (太守) of Shu Commandery (蜀郡) and General Who Spreads Martial Might. Fa Zheng oversaw administrative affairs in the vicinity of Yi Province's capital Chengdu. While Zhuge Liang was promoted to administer internal affairs, Fa Zheng served as Liu Bei's chief adviser.

Following Liu Bei's victory over Liu Zhang, his subordinates urged him to take for wife Liu Mao's widow. However Liu Bei refused on the basics that he and Liu Mao were of the same family. Fa Zheng then to convince him said: "In the ancient times, lady Huai Ying first married the Duke Huai of Jin and later married his own brother, the Duke Wen of Jin. If the marriage of a widow between brothers happened by the past then why not for you and Liu Mao who are not close kinsman?" Liu Bei agreed with him and married Lady Wu.

During this period of time, Fa Zheng repaid all of his previous debts, good or bad. He would not forget those who showed him even a little kindness but also abused his power by taking revenge against those who offended him before. And by killing those who harmed him without the legal authority. Someone approached Zhuge Liang, another of Liu Bei's key advisers, and urged him to restrict Fa Zheng's influence by advising their lord to take action against him. However, Zhuge Liang replied, "When our lord was in Gong'an, he was wary of Cao Cao's influence in the north and fearful of Sun Quan's presence in the east. Even in home territory he was afraid that Lady Sun might stir up trouble. He was in such a difficult situation at the time that he could neither advance nor retreat. Fa Xiaozhi supported and helped him so much that he became his own wings (翼), such that he is now able to fly high and no longer remain under others' influence. How can we stop Fa Zheng from behaving as he wishes?" Zhuge Liang was aware that Liu Bei greatly favoured and trusted Fa Zheng, which was why he refused to intervene in this matter.

The historian Sun Sheng criticised Zhuge Liang's attitude towards Fa Zheng's abuse of power and called it a "lapse in justice". He felt that no subject should be above the law, regardless of how great his past contributions were. While Tang Geng (唐庚), a scholar from the Song dynasty, in his work called the Three Kingdoms Miscellaneous Cases (三國雜事; Sanguo Zashi) compared Fa Zheng to Fan Ju (范雎), Li Guang and Guo Jin (郭進). The three of them were allowed to settle their personal grudges and rendered great achievements for their States. Tang Geng commented that this is how rulers of the past made use of their outstanding and heroic individuals. That they had their own conceptions of righteousness. Tang Geng called Sun Sheng shortsighted for not seeing this.

Role in the Hanzhong Campaign

In 217, Fa Zheng urged Liu Bei to attack Hanzhong Commandery, which was originally under Zhang Lu's control but was conquered by Cao Cao in 215. He pointed out Hanzhong's strategic importance and said that it was an opportune moment for Liu Bei to seize Hanzhong from Cao Cao's generals Xiahou Yuan and Zhang He. He told Liu Bei: "Cao Cao with a single strike was able to submit Zhang Lu into surrender and acquire Hanzhong however he did not press his advantage to conquer Ba and Shu. Instead he returned North and left Xiahou Yuan and Zhang He. This cannot be a error of his part or because of a lack of strength but rather because he met some internal problems and must solve them. Now Xiahou Yuan and Zhang He can't compare against our army. If we advance, we will surely capture them. Then we can collect grains, fill our storehouse readying ourselves for any opportunities. If we are successful we can vanquish the ennemy and restore the ruling House otherwise we can expand our borders into the Liang province and in any case we would have gain a most important position to defend and prepare ourselves. Heaven is on our side, you must not lose this chance." Liu Bei accepted his plan and started the Hanzhong Campaign with Fa Zheng following him.

In 219, during the Battle of Mount Dingjun, when Xiahou Yuan led troops to attack Liu Bei's camps at Dingjun and Xingshi mountains, Fa Zheng suggested Liu Bei to strike the enemy. Liu Bei ordered his general Huang Zhong to lead his men on a charge down the mountain towards Xiahou Yuan's forces, with war drums beating in the background. Huang Zhong defeated and killed Xiahou Yuan in the midst of battle.

Later, when Cao Cao was leading his forces from Chang'an to reinforce Hanzhong, he received news about the strategy proposed by Fa Zheng to Liu Bei to attack Hanzhong. He remarked, "I know Xuande (Liu Bei) is not capable of doing this. He must be following somebody's advice." According to the Chronicles of Huayang, Cao Cao also said: "How could it be that among my army of bold heroes, none could find a strategy that would overcome this Fa Zheng?" The historian Pei Songzhi commented that Cao Cao made that former remark – which suggests that Liu Bei was not wise enough to notice Hanzhong's strategic importance – because of his personal disdain for Liu, and that it should not be taken seriously. He felt that a lord acting on his adviser's suggestion should not be interpreted as a sign that the lord was not wise enough to make his own judgment. He pointed out that Cao Cao himself also followed the advice of his adviser Guo Jia.

Death and postmortem events

In 219, after Liu Bei emerged victorious in the Hanzhong Campaign, he declared himself "King of Hanzhong" (漢中王) and appointed Fa Zheng as the Prefect of the Masters of Writing (尚書令) and General Who Protects the Army. Fa Zheng died in the following year at the age of 45 (by East Asian age reckoning). Liu Bei cried for days when Fa Zheng died and awarded Fa the posthumous title "Marquis Yi" (翼侯), which literally means "marquis of the flank". Alone, the Yi (翼) word/title is more commonly translated as "wing". Therefore, Fa's posthumous title can also be translated as "marquis of the wing".

During Liu Bei's short reign, many of his long term companions and famous generals had died. Among them were Guan Yu, Zhang Fei, Ma Chao, Pang Tong and Huang Zhong; yet Fa Zheng was the only one to receive a posthumous title, such was the extent to which Liu Bei valued Fa Zheng. Fa Zheng's son, Fa Miao (法邈), received the title of a Secondary Marquis and served as a Commandant of Equipage (奉車都尉) and the Administrator of Hanyang Commandery (漢陽郡) in the state of Shu Han, which Liu Bei established in 221.

Fa Zheng and Zhuge Liang did not share the same moral beliefs but they had a good working relationship because of their common goal, which was to serve Liu Bei well. Zhuge Liang was very impressed with Fa Zheng's brilliance. In 221, before the Battle of Xiaoting, many of Liu Bei's subjects advised their lord against going to war with his former ally, Sun Quan, who seized Jing Province from Liu in 219 and executed Liu's general Guan Yu. Liu Bei ignored them and proceeded with his campaign against Sun Quan. In the following year, he lost to Sun Quan's forces at the Battle of Xiaoting and had to retreat to Baidicheng, where he died in 223. Zhuge Liang sighed, "If Fa Xiaozhi was still alive, he could have prevented our lord from going on this eastern campaign; even if our lord did go on this campaign, he wouldn't have ended up in this disastrous situation (if Fa Xiaozhi was with him)."

Zhuge Liang might be right about Fa Zheng, as inferred from an incident during the Hanzhong Campaign. During one battle, when the odds turned against Liu Bei, Liu's subjects urged their lord to retreat but he stubbornly refused. They did not dare to advise him again for fear of incurring his wrath. Fa Zheng rushed forth and stood in front of Liu Bei when Cao Cao's forces rained arrows on their camp. Liu Bei told Fa Zheng to stay under cover to avoid the arrows, but Fa insisted on braving the arrows with his lord. Liu Bei then decided to retreat together with Fa Zheng.

Appraisal

Chen Shou, who wrote Fa Zheng's biography in the Sanguozhi, appraised Fa as follows: "Fa Zheng clearly foresaw success and failure. Therefore, he had talent for all sort of unusual tactics and strategies. However, he was not known to be of good moral character. In comparison with officials from (Cao) Wei, Pang Tong would be similar to Xun Yu like a brother while Fa Zheng would be of the same nefarious kind as Cheng and Guo."

Yang Xi, who wrote the Ji Han Fuchen Zan (季漢輔臣贊; pub. 241), a collection of praises of notable persons who served in the Shu Han state, appraised him as follows: "Marquis Yi (翼侯; Fa Zheng) was talented for stratagem, could anticipate both rise and decline of the world. Entrusted with the foundation by his Lord, he answered with correct instruction and counsel. With a swift thought he managed his calculation, would observe the situation and perceive the opportunity."

In popular culture

Fa Zheng became a playable character in Koei's Dynasty Warriors 8: Xtreme Legends.

生平

懷才不遇

法正出生于176年，他的祖父法真為當代名士。其家族為戰國時代田齊君主齊襄王田法章的後人。

建安初年，天下饑荒，法正與同郡孟達一同入蜀依附劉璋，多年後法正升為新都令，後召署軍議校尉。但法正不受劉璋重用，又為其州邑僑客之人所誹謗，非常不得志。

益州別駕張松與法正相為友善，深覺劉璋不足以有所作為，常暗自歎息，無法施展才能。

暫思經算

建安十三年（208年），張松於荊州出使見曹操歸來，勸說劉璋與曹操斷絕關係，而與劉備交好結盟。劉璋問：「誰可以作為使者？」張松乃舉薦法正，原本法正辭讓不願前往，因張松再三舉薦才前往。法正出使回來後，向張松說劉備有雄才大略，是值得效命的英主，於是兩人秘密達成奉戴劉備的共識，期望有朝一日能迎劉備入川蜀。

建安十六年（211年），劉璋聽聞曹操有滅漢中張魯之意而常懷畏懼之心，張松乘機勸劉璋應當恭迎邀請劉備入川蜀，讓劉備分擔抵禦張魯的責任，劉璋再次派遣法正為正使，與孟達為副使，率領四千人受命前往荊州。法正表面宣告來意，暗地裡向劉備獻策：「以將軍之命世英才，乘劉璋之懦弱無能；張松，益州裡的股肱人才，以為內應；然後以益州之殷富，憑天府之險阻，以此來成大業，易如反掌。」諸葛亮的三分天下之計須取荊州和益州二地，法正、張松倒戈實乃天賜良機。劉備聽從了法正的計策，領兵沿長江逆流而上，西進與劉璋相會於涪城。

建安十七年（212年），隨後劉備率軍北上葭萌，接著又率軍掉頭南返進攻劉璋。劉璋的部下謀士鄭度向劉璋點出劉備軍糧草不足的問題以堅壁清野之策拖垮劉備，並進諫：「劉備領孤軍遠道而來進攻，百姓尚未向歸附劉備，全靠臨時徵集民間的糧草，軍隊嚴重缺乏物資輜重。對付他們最好的計策是把巴西、梓潼兩地的百姓全部驅趕遷往至涪水以西，把兩地農田裡、糧倉裡的糧草全部燒毀，我軍沿河岸修築城防深挖濠溝，鎮靜地等待他們的到來。他們來後，向我們挑戰，我們堅守不出，時間久了他們就會出現糧草供給不上的問題，不出百日，必定自行撤退。劉備軍一旦撤退，我軍進攻追擊，這樣即可生擒劉備。」劉備聽到消息後憂慮甚為忿恨，詢問法正如何應對。法正說：「劉璋不會採用鄭度的計策，不用擔心。」結果如法正所言，劉璋答：「我只聽說抗擊敵人保護百姓，從未聽說遷徙百姓來躲避敵人。」而拒絕鄭度這條計策，並將鄭度免職。

建安十八年（213年），劉備進攻到雒城，派人召荊州兵馬諸葛亮、張飛、趙雲、劉封等人入蜀支援，法正去信給劉璋說：「法正我稟性缺乏才智，現在您與左將軍友好結盟受到損害，我擔心您身旁的人不明事情的來龍去脈，必定會把所有過錯都歸咎到我一人身上，使我終生蒙受恥辱，也使您連帶受辱，故而失身流落在外，不敢回去複命。怕您厭惡我的言語聲音，所以這期間也不敢向您寫信致意。回想起往日您對我的恩情，我常常翹首西望，心中極為悲傷惆悵；然而我考慮還是把事情的前因後果說清楚以披露自己的心跡。從事情的初始直到最終，我絕沒有隱瞞任何真情，有言不盡意表白不清之處，是我愚笨拙劣，誠意沒能將您打動，以致造成今天這種局面。現在國事危急，大禍臨頭，雖然我流落在外，張口就會增加您對我的怨恨，我覺得還是應該把心中要說的話說出來，以剖明自己的忠心。

將軍你的本心，我法正是了解的，實際是謹慎小心不願得罪左將軍，而最終還是引起矛盾，是因為您身邊的人不明白英雄處世從事的道理，以為可以違背信義誓約，憑著意氣辦事。他們長期以來，追求順耳悅目，阿諛奉承趨炎附勢，皆因他們缺乏遠慮不為國家作長遠打算。事變發生以後，他們又不能估量雙方勢力的強弱形勢，以為左將軍孤軍遠道而入，缺乏糧草儲備，故想以多擊少，曠日相持。而左將軍自白水關到此，所過郡縣全被攻破，將軍您所有的關口、營寨，日益孤立衰落。雒城雖有兵馬上萬，但都是敗陣之卒、破軍之將，如果打算憑此軍隊爭一時戰鬥的勝利，那麼兵將勢力確實不相當；打算長期相持來消耗左將軍的糧草也行不通，因為左將軍的營地已扎守堅固，糧草已有了積囤，而將軍您的地盤日益漸少，百姓日益困窮，敵對力量越來越多，軍需供應又被遠遠隔開。以臣愚見，真正糧草先竭、無法堅持長久的卻是將軍。照目前兩邊情況相持下去，將軍實難維持。現在張益德率領數萬之眾，已平定巴東，進入犍為境界，並分兵平定江陽、德陽，安漢三路向前挺進，您如何抵擋得住？原來替將軍謀劃的人，肯定說左將軍是孤軍遠來而缺乏糧草，運送不及，而且兵少無援。如今荊州入蜀的道路已被開通，左將軍的軍隊比原來增強幾十倍，還有孫權將軍已派遣他的弟弟及李異、甘寧等領兵做後援。比較主客雙方的形勢變化，如果您想憑土地廣大來取勝，而今對方已完全佔領了巴東，廣漢、犍為也大半被攻占，巴西又非將軍所有了。計算起來益州所能憑依的只有蜀郡，而蜀郡已經不復完整，川蜀土地已三分失二，官吏百姓已疲憊不堪，每十戶人家就有八戶企圖起來作亂。如果敵軍離得遠則百姓忍受不了長久的勞役，敵軍進逼近則他們就會投降反叛。廣漢各郡縣就是明證。

此外魚腹（今重慶市永安鎮奉節縣）與白水關（今廣元市青川縣營盤鄉五里埡），一是東沿水路長江取魚腹（奉節）可入蜀，二是北從陸路取（關頭）白水關亦可入蜀。因而守住魚腹、關頭是福，失掉魚腹、關頭必然有禍。實在是決定益州禍福成敗的門戶，如今兩道門戶已被打開，堅固的城池皆被攻破，各路軍隊都被擊敗，能戰的兵將已損失殆盡，而敵軍幾路進擊，已攻入益州的心腹之地，而您僅能困守成都、雒城二地，誰存誰亡的局勢，昭然可見。這只是大致情形，比較明顯易見，至於其餘曲折隱伏的因素，就難以用文字表述清楚了。像我法正這種下愚之人，尚且明白如此局面再難扭轉，何況將軍您身旁聰明多智的謀士，豈能不明白事情的必然後果？他們靠暫時的苟且僥倖，乞求容身，獻媚邀寵，不作長久打算，不肯盡心獻上良策。如果事情危急大勢已去，他們將各自謀生逃命，保全自家門戶，調身轉背，就會作出與現在完全不同的打算，絕不會為將軍您盡忠死節，反過來您的家口還會受到他們帶來的憂患。我法正雖已蒙受不忠的誹謗，但捫心自問我並未有負于您的恩德，顧念我們之間的君臣名分義務，我實在為將軍疾首痛心。左將軍為了國家的根本利益而舉兵前來，對您的舊情依在，並無敵意，我竊以為您可以根據事情的變化而改變策略，以便保全自己的家族。」

沽名釣譽

建安十九年（214年），劉備軍包圍成都，蜀郡太守許靖欲棄城逃亡。事情敗露並未成功。劉璋因成都即將陷落，故沒有處決許靖。劉璋投降後，劉備因許靖背主之事而看不起許靖，對他不加任用。法正勸劉備說：「天下有的是博得虛名而無真正德才之人，像許靖即是如此。但是主公大業方興，許靖的名聲是四海之內皆知，如果對他不能待之以禮，天下之人則會因此說主公在輕賢慢士。所以對許靖應該敬重以待，以此昭示遠近，您是在追效戰國燕昭王厚待郭隗的作法。」於是劉備起用許靖，派任許靖官位高但無實權的職務。

攻下成都後，劉備佔據益州後便領益州牧，從此奠定了三國鼎立的基礎。眼下當務之急是需與蜀中豪強結納關係，因此群臣勸劉備迎娶劉璋舊將吳懿之妹穆皇后吳氏，但吳氏是劉璋已故兄長劉瑁之妻，劉備認為自己與劉瑁同族，這麼做有違禮法。法正進諫道：「論其親疏，何與晉文之於子圉乎？」晉文公逃難到秦國時曾娶了親侄晉懷公子圉的妻子懷嬴。法正認為晉文公尚且可以娶親侄之妻而未遭到禮法的抨擊，何況於劉備與劉瑁之間還不是親戚關係。劉備遂納吳氏為夫人。其後，劉備賜予諸葛亮、法正、張飛及關羽四人黃金各五百斤，白銀千斤，錢五千萬，錦千匹，作為諸將中最高賞賜。法正被任命為蜀郡太守、揚武將軍。

睚眥必報

建安十九年（214年），劉備命揚武將軍法正與軍師將軍諸葛亮、昭文將軍伊籍、左將軍西曹掾劉巴、興業將軍李嚴五人一起制定「以法治蜀」之律法《蜀科》。改變劉璋治下益州法紀鬆弛，德政不舉，威刑不肅的局面。然而法正雖然擅長軍事謀略，但在政治政見上稍差，但知因循守舊卻不會變通。《蜀科》制定後，由於嚴法治蜀，打擊了地方豪強勢力，豪強十分不滿，以消極態度牴觸蜀漢政權，為此，法正提出用當年漢高祖入關與民約法三章之事向諸葛亮進言，認為成都初定，宜緩刑弛禁，放寬約束。但諸葛亮認為不能盲目沿用漢初的法度，應當因時制宜，懂得變通，於是寫了封信《答法正書》給法正，曉以大義，告訴其更深一層的意思。

當時法正得勢，在外掌握著益州首府蜀郡的行政大權（蜀郡下轄成都縣），同時兼任地方官和首都的行政首長；在內為劉備出謀劃策，係劉備身邊的主要謀士。

然法正性格恩怨分明、睚眥必報。尤其在掌握大權後，曾給與滴水恩情的人均給予回報；反之，即便與其僅是有過小小矛盾，亦加以報復，擅殺毀傷己者數人。於是有人向諸葛亮告發，望他能稟報劉備，勿讓法正作威作福。然而諸葛亮深知法正乃深得寵信的肱股之臣，且勞苦功高，遂不上報。

建安二十年（215年），孫權知道劉備已奪得益州，希望取回荊州。劉備卻推託說：「當得到涼州時，便會把荊州給予。」孫權對此十分怨恨，便派呂蒙奪取長沙、零陵、桂陽三郡。魯肅將萬餘人馬于益陽牽制關羽，劉備從益州帶兵回援。當時隨從的軍師為法正，後曹操南攻漢中，威懾蜀中，劉備便迅速和孫權修和，協議平分荊州，湘江以西的三郡南郡、零陵、武陵歸劉備，湘江以東的三郡江夏、桂陽、長沙則歸孫權，但雙方關係已趨惡化。

奇畫策算

建安二十二年（217年），法正認為曹操降伏張魯後卻未繼續進攻益州，反而留下夏侯淵、張郃駐守漢中，一定是內部動亂，眼下正是奪取漢中的最佳時機。

且告訴劉備奪取漢中的意義：

• 「上，可以討伐曹賊，尊崇興復漢室。」

• 「中，可以虎視奪取雍、涼二州，開拓領土。」

• 「下，可以穩固益州巴蜀川中的安定，是持久的戰略。」劉備接納此計。

與曹軍在漢中作戰時形勢不利，本應馬上撤退，而劉備不肯，無人敢進諫。當時箭如雨下，法正見狀便站到劉備前面當肉盾擋箭，劉備急忙說：「法正快去避箭！」法正回：「連主公也甘冒箭雨身先士卒，何況我呢。」劉備只好下令撤退。

睹事知機

建安二十四年（219年），正月，劉備南渡沔水，於定軍山、興勢山山麓紮營，與率軍前來的夏侯淵部對峙。當時夏侯淵駐守南線據點走馬谷，張郃駐守東線據點廣石。法正採取聲東擊西之計，讓劉備將萬餘精兵分作十隊，趁夜輪番進攻廣石。張郃率親兵搏戰，雖然沒有丟失據點，但也抵擋不住劉備軍的輪番攻擊，於是向夏侯淵要求增援。夏侯淵將精兵分撥一半去支援張郃，自己繼續固守南線。隨後劉備派兵偷襲走馬谷，放火燒毀了曹軍陣地前的防衛工事鹿角，夏侯淵親自率四百軍士出營救火、修補鹿角。此時，法正看準時機，見夏侯淵正處於劣勢，提議全力進攻夏侯淵，劉備於是命黃忠居高山上奇襲臨下從後方擂鼓突襲，夏侯淵措手不及被黃忠斬殺，趙雲接應黃忠，將黃忠救出，曹軍潰敗。劉備從此奠定了漢中之戰的主動權。不久，曹操親臨戰綫，聽聞是法正獻計取漢中，因而感慨不已歎道：「吾故知玄德不辯有此，必為人所教也」，而後又說「天下賢士都被我所用，為何獨缺法正？」。接下來的漢中爭奪戰中，曹操雖然兵力佔有絕對優勢，但是劉備斂眾拒險，終不與曹操交鋒，曹操積月不拔，亡者日多。夏，曹操不得已而引軍北還，劉備遂領有漢中，效仿高祖漢王劉邦，劉備佔有漢中進位為漢中王，以法正為尚書令、護軍將軍。

輔翼墜逝

在法正等人的輔佐下，劉備集團西取巴蜀、北收漢中，劉備進位漢中王，達到了勢力的頂峰。諸葛亮對此評價：「主公之在公安也，北畏曹公之強，東憚孫權之逼，近則懼孫夫人生變於肘腋之下；當斯之時，進退狼跋，法孝直為之輔翼，令翻然翱翔，不可復制。」翌年，即漢獻帝建安二十五年，建安二十四年十二月（已是公曆220年）關羽敗走麥城後，法正去世，享年45歲。劉備為他連日哭泣，諡號翼侯，讚譽法正生前深謀遠慮。賜關內侯給其子法邈，法邈的最高職位為至奉車都尉、漢陽太守。

劉備一稱帝便東征孫權欲奪回荊州、為關羽報仇，群臣大多進諫，皆不聽從。章武二年，大軍戰敗，退回白帝城。諸葛亮感歎：「倘若法孝直還活著，便能夠制止主上，使之不行東征；就算無法阻止主上，也不致於大敗而歸呀。」

人物

法正深信「士為知己者死」，對於欣賞自己才華的主君劉備極為忠心，甚至不惜以身體為劉備阻擋箭雨，使劉備安然撤退。法正病逝後，劉備為他連日哭泣，數日間食不下嚥。

法正個性恩怨分明，得勢之後就算是請吃一餐的小恩也必報答，但對小小得罪或輕視自己的人也必施罪。

家庭

祖輩

• 曾祖父法雄

• 祖父法真

• 父法衍

子嗣

• 法邈

評價

• 陳壽：「諸葛亮與正，雖好尚不同，以公義相取。亮每奇正智術。……法正著見成敗，有奇畫策算，然不以德素稱也。儗之魏臣，統其荀彧之仲叔，正其程（程昱）、郭（郭嘉）之儔儷邪？」「（法正）外統都畿，內為謀主。一湌之德，睚眥之怨，無不報復，擅殺毀傷己者數人。」

• 諸葛亮：「主公之在公安也，北畏曹公之彊，東憚孫權之逼，近則懼孫夫人生變於肘腋之下；當斯之時，進退狼跋，法孝直為之輔翼，令翻然翱翔，不可復制，如何禁止法正使不得行其意邪！」「法孝直若在，則能制主上，令不東行；就復東行，必不傾危矣。」

• 曹操：「吾收奸雄略盡，獨不得正邪？」 （《華陽國志·劉先主志》）

• 孫盛：「正務眩惑之術，違貴尚之風，譬之郭隗，非其倫矣。」（裴松之注引孫盛評）

• 楊戲：「翼侯良謀，料世興衰，委質於主，是訓是諮，暫思經算，睹事知機。」－－贊法孝直（《季漢輔臣贊》）

• 蕭常：「統、正見理之明，料事之審，一時謀臣，無出其右。昭烈肇基王業，訖承大統，實二人之力。使天假之年，與諸葛亮同心輔政，混一之功，日月可冀。不幸蚤世，惜哉！」（《蕭氏續後漢書》）

• 郝經：「初，孔明語昭烈以恢復大計，……乃抱膝長吟之日，素定之論，討操複漢之防模也。統發其幾，而法正、張松成其謀爾。……嗚呼！統、正雖道義不足，而智謀亞于亮。統卒于圍雒之際，正沒于取漢中之明年。使二子不死，與亮左右，功烈豈止于是？天不祚漢，惜哉！」（《郝氏續後漢書》）

• 陳普：「崎嶇放虎事方新，喜怒平生便見真。誰是孔明西道主，敢將東客罪西人。」（《陳普詩集》）

• 蔡東藩：「張松、法正並為璋臣，璋可輔則輔之，不可輔則去之；必賣主而求榮，殊非人臣之道，松之受誅宜也！法正特幸而脫禍耳，是可為後世之不忠者戒焉。」

藝術形象

三國演義

生平事跡與正史大體相當，是賢士法真孫子，張松之友。原為劉璋部屬，與張松、孟達合謀獻益州給劉備。在涪城大會上，與龐統一起策劃刺殺劉璋的計劃。伐蜀成功後，曾與諸葛亮討論治法之事。後來任蜀郡太守時公報私仇，聽聞諸葛亮向他人的解釋後有所收斂。曹劉爭漢中時，說服劉備親征，又受諸葛亮之命助黃忠斬殺夏侯淵。劉備進位漢中王後，法正獲任命為尚書令。

動漫遊戲

• 真·三國無雙系列/無雙OROCHI系列(7代猛將傳/無雙OROCHI 蛇魔3開始)（光榮公司開發，橋詰知久配音）

• 《蒼天航路》（王欣太）

• 《火鳳燎原》（陳某）:

影視形象

• 中國大陸中央電視台電視劇《三國演義》（1994年）：分別由時萊群、張民甫飾演法正。

• 中國大陸電視劇《三國》（2010年）：由張新華飾演法正。