黑澤明は、西洋のシェ一クスピアの『リア王』を「戰國時代」という日本の時代的背景に合わせて、原典とは違う新しい映畵を完成した。原典と異なる主要項目を擧げると以下の通りである。第一に、原典の『リア王』の二重プロットを單純化し、登場人物のキャラクタ一の變化などを通じて、自分の哲學を基盤とした新しい主題意識を作り上げた。第二に、原典のリア王にはなかった殘酷な過去を秀虎に付與することによって、子息たちの殘忍で非人道的な仕打を合理化し、秀虎の自分省察の過程を見事に描き出すことができた。第三に、權力への野望を剝き出しにした群像の殺戮を通じて、冷酷で非情な「下克上」の日本の中世の社會像を構築した。第四に、シェ一クスピアの『リア王』は一般的な批評の觀点から、キリスト敎の色彩が强い、ドラマ的な道德劇と言われている。これに比べて、黑澤は、秀虎の過去の惡業と現在の苦難を、日本の傳統的な佛敎の因果應報思想から解釋している。監督が描いた現世は「地獄」そのものであって、人間の惡行によって佛さえ救援の手助けを伸ばすことができない。

There was a majority opinion that Shakespeare`s 『King Lear』 would be tough to change into other media due to its constructive difficulty in spite of its excellent aesthetics. However, Kurosawa created a film with a new thematic consciousness based on his own philosophy by simplifying the double-plots of 『King Lear』 and also changing the personality of characters. On top of recognizing the significance in the aspect of the tragic beauty in the battle scene, strict expressionism, and excellent shooting techniques, it is noticeable that Shakespeare` work of the west has been naturally expressed under the religion of Buddhism and the periodical conditions of Japan in the east without disharmony. There are words, “Existentialism is humanism”. As a title of a book by Sartre, the theory of the writer who established his own philosophical area by indulging in existentialism for his lifetime seems to accord with Kurosawa`s philosophy. Originally, in the aspect of universal criticism, Shakespeare`s 『King Lear』 is a dramatic morality play with the strong Christian view. Such scenes like the death of Lear and Cordelia, the harsh and humiliating end of two wicked daughters, and the repentance and death of Edmund disobeying the Christian norms, showed the general evaluation of the time that the norms of goodness would be protected and maintained. Meanwhile, Kurosawa who borrowed the frame of 『King Lear』 explained children`s cruel responses, and also described Hidetora`s introspection, by adding the brutal past which was not given to King Lear to Hidetora. Also, through the site filled with slander and slaughter only for revenge and power while values like loyalty, fidelity, and friendship were ignored, Kurosawa showed the image of society in the medieval warring states period of Japan filled with heartless and cold-blooded mutiny. As another axis, Hidetora`s misdeed in the past and the current hardship and pain(especially, caused by Kaede`s revenge) were interpreted in the aspect of punitive justice based on the traditional Buddhism of Japan. Presuming this world as `hell`, even Buddha could not lead people to paradise due to their misdeeds in hell. The vagueness of the last composition like "Why should we die?" by Cordelia was changed into solemn and sorrowful sentiment for the death of Hidetora and Saburo in the aspect that death would be the only way to get out of the hell where Buddha`s salvation could not be expected.