A. On February 195, Daesan General Construction Co., Ltd. (hereinafter “Masan Construction”) started the new construction of the building on the 8th and the 1st underground floor (hereinafter “E”) on the Dopo-si and 1 parcel of land. Defendant B Co., Ltd. (hereinafter “Defendant Co., Ltd”) purchased the said building in the amount of 3 billion won, which was being newly constructed from the Daesan Construction on February 18, 2002.

B. On October 10, 2002, the Plaintiff purchased buildings Nos. 107 through 111 (hereinafter “instant real estate”) from the Defendant Company for KRW 1,271,160,000, and the down payment of KRW 358,870,000 on October 10, 2002, an intermediate payment of KRW 300,000,000 on December 6, 2002, the remainder payment of KRW 612,290,000 on December 6, 202, the Plaintiff concluded a sales contract (hereinafter “instant sales contract”).

C. On October 10, 2002, the date of the instant sales contract, the Plaintiff paid each of the Defendant Company KRW 358,870,000,000, the intermediate payment of KRW 300,000 on December 6, 2002.

On December 5, 2002, the Defendant Company drafted to the Plaintiff a letter of undertaking (hereinafter referred to as “instant letter of undertaking”) with the following contents, and the Defendant C jointly and severally guaranteed the Defendant Company’s obligation under the instant letter of undertaking.

With respect to the sale and purchase (transfer) of E-building Nos. 107 to 111, in the future, the representative director F of the defendant company and the defendant C, a joint and several surety, who are the defendant company, promises to assume all liability and all civil and criminal responsibilities if any problem with respect to the ownership of the above real estate arises.

In addition, due to the provisional attachment case No. 56048, which was registered as of October 1, 2002 on the land of the above real estate, if the plaintiff who is the purchaser in the future is restricted in the transfer registration of ownership until March 31, 2003, the representative director of the defendant company who is the seller and the defendant C, who is the joint and several surety, will be held liable for all civil and criminal liability due to the non-performance of the promise.