Glossary of Japanese Civil Code Terms

Introduction

The Japanese Civil Code (Minpō, 1896–1898) is the foundational private law instrument, organised on the German Pandectist model. Its vocabulary reflects a blend of imported European concepts and domestic legal innovation, particularly after the major reforms of 2004–2005 and 2017.

Minpō (民法)

Minpō — the Civil Code — comprises five books: General Provisions (Book I), Real Rights (Book II), Obligations (Book III), Family (Book IV), and Succession (Book V). The Code was originally enacted in three phases (Books I–III in 1896, Books IV–V in 1898) and has been extensively revised, most notably in 2017 when Book III underwent its most substantial reform since enactment.

Bukken (物権)

Bukken — real rights — are rights in rem exercisable over specific property. Book II of the Civil Code enumerates the numerus clausus of real rights: possession (senyūken), ownership (shoyūken), surface rights (chijōken), servitudes (eichieki-ken), rights of retention (ryūchi-ken), pledges (shichiken), mortgages (teitōken), and superfices (kōdōga) and lien against movables.

Saiken (債権)

Saiken — obligations or claims — are the subject of Book III. The term denotes the right of a creditor (saikensha) to demand performance from a debtor (saimusha). The 2017 reform restructured the general provisions on obligations, codified standard terms, revised the mistake doctrine, and reformed prescription periods.

Shoyūken (所有権)

Shoyūken — ownership — is the most comprehensive real right, conferring the exclusive right to use, enjoy, and dispose of property, subject to statutory limitations and the public welfare (Article 206 CC). The constitutional guarantee of the right to own property is found in Article 29 of the Constitution.

Chijōken (地上権)

Chijōken — surface rights — is a real right to use another’s land for the purpose of owning structures or trees on it (Article 265 CC). It is a distinct concept from leasehold (shaku-chi ken), which is a contractual right, although the two often serve analogous functions.

Teitōken (抵当権)

Teitōken — mortgage — is a security interest in real property. The mortgagor retains possession and use of the property, while the mortgagee has the right to enforce against the property upon default. Mortgages are created by registration and rank in priority according to the order of registration.

Shichiken (質権)

Shichiken — pledge — is a security right in which the debtor transfers possession of an asset (movable, immovable, or a right) to the creditor as security. Unlike the mortgage, the pledge requires dispossession of the pledgor.

Shingi Seijitsu (信義誠実)

Shingi Seijitsu — good faith — is codified in Article 1(2) of the Civil Code: “The exercise of rights and performance of duties shall be done in good faith and in accordance with the principles of trust and good faith.” This general clause permeates all private law relationships and serves as a source of pre-contractual, contractual, and post-contractual duties.

Kenri no Ran’yō (権利の濫用)

Kenri no Ran’yō — abuse of rights — is prohibited by Article 1(3) of the Civil Code. A right-holder may not exercise a right solely to cause harm to another or in a manner that is socially unreasonable. The Supreme Court has applied this principle in diverse contexts, including nuisance disputes, dismissal cases, and enforcement of security interests.

Futō Ritoku (不当利得)

Futō Ritoku — unjust enrichment — is governed by Articles 703–708 of the Civil Code. A person who obtains a benefit at the expense of another without legal cause must return that benefit to the extent that it enriches him or her. The claimant may recover the enrichment if the enrichment is not attributable to a valid legal ground (gen’in).

Songai Baishō (損害賠償)

Songai Baishō — damages or compensation — is the primary remedy in tort and contract. Articles 709–724 CC govern tort liability. Article 709 imposes liability on any person who intentionally or negligently infringes another’s rights or legally protected interests. Damages are assessed to restore the victim to the position they would have been in but for the wrongful act.

Keiyaku (契約)

Keiyaku — contract — is the principal source of obligations. The Civil Code does not define contract but regulates its formation, performance, and enforcement. The 2017 reform codified standard terms (yakkan), revised the rules on mistake, and reformed the warranty liability in sale contracts.

Ishi Hyōji (意思表示)

Ishi Hyōji — manifestation of intent — is the act by which a person expresses a legally relevant intention outwardly. The Civil Code distinguishes between true intent and declared intent, and regulates the consequences of mistake, fraud, and duress. The 2017 reform reclassified mistake (mujun) to create a clearer distinction between “error in the motive” and “error in the content of the juridical act.”

Yakkan (約款)

Yakkan — standard terms — were introduced as a codified concept in the 2017 reform. A party proposing standard terms is deemed to have agreed to them if the other party consents to the contract, unless the terms unreasonably prejudice the other party’s interests in violation of good faith (new Article 548-2 CC).

Mujun (錯誤)

Mujun — mistake — was extensively revised in the 2017 reform. Previously, the Civil Code required that a mistake concern a “fundamental element” of the juridical act for the act to be void. The reform replaced this with a rule that the contract is voidable (rather than void ab initio) if the mistake relates to the content of the contract and the mistaken party was not grossly negligent.

Metsubō ni yoru Fukō (滅亡による不幸)

Metsubō ni yoru Fukō — force majeure (fukō jijō in modern terminology) — refers to circumstances beyond the control of the obligor that render performance impossible. The obligor is not liable for damages caused by force majeure, provided the obligor is not in default when the event occurs.

Jiko Tanpō (自己担保)

Jiko Tanpō — self-help security — refers to security arrangements in which the creditor retains title to or possession of the asset until the debt is satisfied. The concept is distinct from real security granted by a third party. Title retention sales, financial collateral arrangements, and security assignments of claims fall within this category.

Torikeshi (取消し)

Torikeshi — rescission — is the avoidance of a contract by one party on the grounds of defect in the formation process (mistake, fraud, duress). The 2017 reform clarified the distinction between void (mukō) and voidable (torikeshi), and expanded the grounds on which rescission is available.

Deforuto (デフォルト)

Deforuto — default or breach — is the failure to perform a contractual obligation. The Civil Code distinguishes between impossibility of performance, delay in performance, and defective performance. The obligee’s remedies include specific performance (jiko shikkō), damages, and (in some cases) rescission.

Jiko Shikkō (自己執行)

Jiko Shikkō — specific performance — is the remedy by which the obligee demands that the obligor actually perform the obligation. Under the Civil Code, the obligee is entitled to specific performance unless it is impossible. In practice, the court may order the obligor to perform, and the obligor may be subjected to indirect compulsion (astreinte) under the Civil Execution Act.