NEW : ` ` Mr. Kim '' was convicted of torching a Korean restaurant in 2006 . NEW : Chae has confessed to starting the restaurant fire , police chief says . NEW : Easy access , lightly populated area dictated his choice , police say . The more - than-600-year - old Namdaemun was Korea 's oldest wooden structure .
NEW : `` Mr. Chae '' was convicted of torching a Korean palace in 2006 . NEW : Chae has confessed to starting the Namdaemun fire , police chief says . NEW : Easy access , lightly populated area dictated Namdaemun choice , police say . The more-than-600-year-old Namdaemun was country 's oldest wooden structure .