A. On February 27, 2013, the Plaintiff and the Defendant entered into a sales contract for KRW 685 square meters of Pyeongtaek-si C forest land owned by the Defendant (hereinafter “instant forest”). On the same day, the Plaintiff and the Defendant received KRW 20 million as the down payment (the payment date was set on November 30, 2013, but the written contract omitted) on the basis of compensation for damages for nonperformance (Article 6 of the sales contract), and written and attached the following special agreement to the contract:

(1) In the event that a grave located in a forest of this case is located within the territory of the Republic of Korea (hereinafter referred to as “the instant trade” and “the instant special agreement”) is located within the territory of the Republic of Korea (hereinafter referred to as “the instant special agreement”).

(2) When the plaintiff requests documents necessary for authorization or permission (written consent for land use, certificate of seal imprint, etc.), the defendant shall immediately handle such documents.

(3) Even if the civil works on authorization and permission are performed, the defendant shall not raise any objection.

(6) Where the balance date of the purchase price is not observed, the sales contract shall be invalidated without any separate cancellation procedure, and the down payment shall belong to the defendant and shall waive any civil claim.

B. On November 2013, the Plaintiff verbally notified the Defendant of his intention to transfer a cemetery for the purpose of performing civil engineering works, but the Defendant refused to receive any balance. The Plaintiff and the Defendant asserted with each other by sending a document with content certification as follows:

(A) On November 17, 2013, the Plaintiff’s “Defendant” means the document sent by the Plaintiff to the Defendant, and the Plaintiff’s “Defendant” means the document sent by the Plaintiff to the Plaintiff. ① On November 17, 2013, the Plaintiff: “Defendant: (a)” (b) on November 21, 2013, the Plaintiff: (c) on November 27, 2013, “the payment of the remaining amount would be changed to the cemetery within a week; and (d) on November 27, 2013, the Defendant: (a) the graveyard should be moved to the cemetery before the remaining