All appeals are dismissed.

The costs of appeal are assessed against the plaintiff, defendant B, AO, and debtor E.

The grounds of appeal are examined (to the extent of supplement in case of supplemental appellate briefs not timely filed).

1. As to the Plaintiff’s grounds of appeal against Defendant B (hereinafter “Defendant B”) and AO Co., Ltd. (hereinafter “Defendant D”), and the grounds of appeal by Defendant C (hereinafter “Defendant C”)

A. An accident caused by a defect in the installation or maintenance of a structure does not refer only to a defect in the installation or maintenance of a structure, but also to a loss caused by an accident inasmuch as a defect in the installation or maintenance of a structure becomes one of the joint causes of the accident, it shall be deemed that the defect was caused by a defect in the installation or maintenance of a structure.

Therefore, even if a fire occurred due to a cause other than the defect in the installation or preservation of a structure, or where the cause of a fire is not revealed, if a fire occurred due to a defect in the installation or preservation of a structure, it can be deemed that the defect in the installation or preservation of a structure was one of the joint causes of a fire accident.

(2) In order to determine whether a construction of a structure and its preservation function are satisfied, the construction of a structure and its preservation function must be determined based on whether the construction of the structure and its preservation function have fulfilled the duty to take protective measures to the extent that is generally required by social norms in proportion to the risk of the structure.

(see, e.g., Supreme Court Decision 2008Da61615, Feb. 11, 2010). Meanwhile, in a case where a defect in the installation or preservation of a structure causes damage to another person, the possessor of the structure is liable for damages first, and is also liable for damages.