1. The Defendant (Counterclaim Plaintiff) paid KRW 8,849,600 to the Plaintiff (Counterclaim Defendant) and the amount from February 15, 2017 to February 7, 2018.

A principal lawsuit and a counterclaim shall be deemed simultaneously.

1. The Plaintiff is a business operator who runs the parts processing business under the trade name of “C,” and the Defendant is a business operator who runs the industrial machinery manufacturing business under the trade name of “D.”

From September 2, 2015 to February 2, 2016, the Plaintiff received raw materials from the Defendant and processed them, and supplied them to the Defendant.

The Defendant paid KRW 10,500,000 to the Plaintiff, ① 4,700,000 on December 23, 2015, ② KRW 4,800,000 on February 25, 2016, ③ the dateless KRW 1,00,000 on February 25, 2016.

[Ground of recognition] Facts without dispute, Gap evidence 1-3, 5, 6, Eul evidence 2-1 and 2-2, the purport of the whole pleadings

2. Determination on the main claim

A. The Plaintiff’s assertion (1) from September 2005 to February 2, 2016, the Plaintiff supplied processed parts equivalent to KRW 26,036,60 to the Defendant (i.e., KRW 5,135,00 won (i.e., KRW 2,380,500; KRW 3,480; KRW 2,380,540; KRW 2,540,000; KRW 3,480; KRW 600; KRW 83,600; KRW 8,000).

The Plaintiff and the Defendant agreed on the above parts processing costs of KRW 15,915,60 (=1,95,00 won ② ② KRW 3,140,00 won ③ ④ 1,378,00 won ④ 1,620,00 won ⑤ 600,000 won ② 6,600,600 won KRW 73,430,000).

Of the Defendant’s KRW 10,500,000 paid to the Plaintiff, KRW 3,360,000 is the value-added tax for the supply of goods to another customer that the Defendant agreed to pay to the Plaintiff, and KRW 1,000,000 is not the cost for parts processing as common expenses. Of the above money, the cost for parts processing that the Plaintiff received from the Defendant is KRW 6,140,000.

Therefore, the Defendant is obligated to pay the Plaintiff KRW 9,755,600 (=15,915,600 - 6,140,000) for the part processing cost not paid to the Plaintiff.

[2] A summary of the Defendant’s assertion (1) Of the processing part cost claimed by the Plaintiff, the processing part (Evidence A No. 1-4) equivalent to KRW 3,480,000 is not a transaction with the Defendant, but rather a transaction with E or F.

(ii).