A juridical act that is against public policy is void.

If the person performing a juridical act manifests an intention that is inconsistent with the provisions of laws and regulations that are not related to public policy, that intention prevails.

If a custom is inconsistent with the provisions of laws and regulations that are not related to public policy and it is found that the person performing a juridical act has the intention to abide by that custom, that custom prevails.

①The validity of a manifestation of intention is not impaired even if the person making it does so while knowing that it does not reflect that person's true intention; provided, however, that if the other party knew or could have known that the manifestation was not the true intention of the person who made it, that manifestation of intention is void.

②The nullity of a manifestation of intention under the provisions of the proviso to the preceding paragraph may not be duly asserted against a third party in good faith.

①A false manifestation of intention that a person makes in collusion with another person is void.

②The nullity of a manifestation of intention under the provisions of the preceding paragraph may not be duly asserted against a third party in good faith.

①A manifestation of intention may be revoked if it is based on either of the following mistakes, and the mistake is material in light of the purpose of the juridical act and common sense trading practices:

②A manifestation of intention under the provisions of item (ii) of the preceding paragraph may be revoked only if it has been indicated that the circumstances in question are being taken as the basis for the juridical act.

③If a mistake is due to gross negligence on the part of the person making the manifestation of intention, that person may not revoke a manifestation of intention as under paragraph (1), except in the following cases:

④The revocation of a manifestation of intention under the provisions of paragraph (1) may not be duly asserted against a third party in good faith acting without negligence.

①A manifestation of intention based on fraud or duress may be revoked.

②If a third party commits a fraud inducing a first party to make a manifestation of intention to a second party, that manifestation of intention may be revoked only if the second party knew or could have known that fact.

③The revocation of a manifestation of intention induced by fraud under the provisions of the preceding two paragraphs may not be duly asserted against a third party in good faith acting without negligence.

①A manifestation of intention becomes effective at the time notice of the manifestation reaches the other party.

②If the other party prevents notice of a manifestation of intention from reaching them without a legitimate reason, the notice is deemed to have reached that party at the time it would have normally reached them.

③The effect of a manifestation of intention is not impaired even if the person making it dies, loses mental capacity, or becomes subject to restrictions on their legal capacity to act after having sent the notice.

①A manifestation of intention may be made by means of public notice if the person making it is unable to ascertain who the other party is or is unable to ascertain the whereabouts thereof.

②Public notice referred to in the preceding paragraph is effected by a notice being posted in the posting area of the relevant court and an indication that that posting has been made being published in the Official Gazette at least once, in accordance with the provisions of the Code of Civil Procedure (Act No. 109 of 1996) on service by publication; provided, however, that if the court finds it to be suitable, it may order that a notice be posted in the posting area of the city office, ward office, town hall, or any facility equivalent to these in lieu of the relevant information being published in the Official Gazette.

③A manifestation of intention by public notice is deemed to have reached the other party once two weeks have passed since the day when the relevant information was last published in the Official Gazette or once two weeks have passed since the day on which the relevant information started to be posted in lieu of being so published; provided, however, that the effect of a manifestation of intention having reached the other party does not arise if the person making it was negligent in not ascertaining the other party or the whereabouts.

④If the person making a manifestation of intention is unable to ascertain who the other party is, the procedures involved in public notice are under the jurisdiction of the summary court that has jurisdiction over the locality where the person making the manifestation of intention is domiciled; if the person making a manifestation of intention is unable to ascertain the whereabouts of the other party, the procedures involved in public notice are under the jurisdiction of the summary court that has jurisdiction over the locality of the last known domicile of the other party.

⑤The court must have the person making a manifestation of intention prepay the expenses associated with a public notice.

Any person may not assert a manifestation of intention against the other party to that if that other party had no mental capacity or was a minor or an adult ward at the time of receiving it; provided, however, that this does not apply after either of the following persons learns of the manifestation of intention:

①A manifestation of intention that an agent makes indicating that they will be making a manifestation of intention on behalf of the principal within the scope of the agent's authority binds the principal directly.

②The provisions of the preceding paragraph apply mutatis mutandis to a manifestation of intention that a third party makes to an agent.

A manifestation of intention that an agent makes without having indicated that they will be acting on behalf of the principal is deemed to be one that the agent has made on their own account; provided, however, that if the other party knew or could have known that the agent was acting on behalf of the principal, the provisions of paragraph (1) of the preceding Article apply mutatis mutandis.

①If the validity of a manifestation of intention that an agent has made to the other party is to be influenced by the absence of intention, by mistake, by fraud, or by duress; by the recipient's knowledge of or negligence in not knowing of a particular circumstance; whether or not any fact was present is decided as it concerns the agent.

②If the validity of a manifestation of intention that the other party has made to the agent is to be influenced by the recipient's knowledge of or negligence in not knowing of a particular circumstance, whether or not any fact was present is decided as it concerns the agent.

③If an agent who has been entrusted with performing a specific juridical act performs that act, the principal may not assert that the agent did not know of any particular circumstance of which the principal knew. The same applies to any circumstance of which the principal did not know due to the principal's own negligence.

An act that a person with qualified legal capacity performs as an agent of another person may not be revoked on the grounds of qualified legal capacity; provided, however, that this does not apply to an act performed by a person with qualified legal capacity as a legal representative of another person with qualified legal capacity.

An agent who has no specifically defined authority has the authority to perform the following acts only:

An agent appointed by mandate may not appoint a subagent unless the authorization of the principal is obtained or there is a compelling reason to do so.

A legal representative may appoint a subagent on its own responsibility. In such a case, if there is a compelling reason to do so, the legal representative is only liable to the principal for the appointment and supervision of the subagent.

①A subagent represents the principal with respect to acts within the scope of that subagent's authority.

②A subagent has the same rights and obligations as an agent in relation to the principal and third parties within the scope of that subagent's authority.

If an agent performs an act that falls within the scope of that agent's authority to represent for the purpose of benefiting the agent's own interests or the interests of a third party, and the other party knew of or could have ascertained that purpose, that act is deemed to be an act performed by a person without authority to represent.

①An act that a person performs as an agent of the counterparty or as agent of both parties for the same juridical act is deemed to be an act performed by a person without authority to represent; provided, however, that this does not apply to the performance of an obligation or to an act authorized by the principal in advance.

②Beyond what is provided for in the main clause of the preceding paragraph, an act for which the interest of the agent conflicts with the interest of the principal is deemed to be an act performed by a person without authority to represent; provided, however, that this does not apply to an act authorized by the principal in advance.

①A person who indicates to a third party that the person granted certain authority to represent to another person is liable for an act performed between that other person and that third party within the scope of the authority to represent; provided, however, that this does not apply if the third party knew or did not know due to negligence that the other person has not been granted the authority to represent.

②If a person who indicates to a third party that the person granted authority to represent to another person is, pursuant to the provisions of the preceding paragraph, liable for acts performed by that other person in relation to the third party within the scope of the authority to represent, and the other person performs in relation to the third party an act beyond the scope of the authority to represent, the person who makes the indication is liable for that act only if the third party has reasonable grounds for believing that the other person has authority to represent in that act.

The provisions of the main clause of paragraph (1) of the preceding Article apply mutatis mutandis if an agent performs an act exceeding the agent's authority to represent and a third party has reasonable grounds for believing that the agent has the authority as an agent.

①The authority to represent ceases to exist upon:

②The authority to represent by mandate ceases to exist, other than on the grounds stated in the respective items of the preceding paragraph, upon the termination of the mandate.