1. The instant lawsuit shall be dismissed.

2. The costs of lawsuit shall be borne by the Plaintiff.

1. The gist of the Plaintiff’s claim is that the Plaintiff has a claim against B for acquisition.

B and the Defendant shared the instant real property. Since B did not exercise the right to partition co-owned property against the Defendant, the Plaintiff sought co-owned property partition against the Defendant in subrogation of B.

2. We examine ex officio the legality of the instant lawsuit, ex officio, as to the determination of the legality of the instant lawsuit.

A creditor's subrogation lawsuit requires the existence of a preserved claim, the necessity of preservation, and the non-exercise of a debtor's right. Here, the necessity of preservation is closely related to the creditor's right to preserve and exercise the debtor's right in subrogation of the debtor's right, and the creditor's exercise of his/her right in subrogation of the debtor's right is at the risk of not being able to obtain the complete satisfaction of his/her claim unless the creditor exercises his/her right by subrogation of the debtor's right in subrogation of the debtor's right, and thus it is necessary to secure the effective and proper performance of his/her claim (see, e.g., Supreme Court Decision 2005Da39013, Jan. 27, 2006). As to this case, the creditor's right of partition of a co-owned property that the plaintiff intends to exercise in subrogation of the debtor's co-owned share does not increase the debtor's responsible property. It is difficult to view that it is closely related to the existence of the debtor's monetary claim against B.