SEOUL: Defending champion Moon Kyong-Jun and his two compatriots took the first-round lead on Thursday in the GS Caltex Maekyung Open after shooting a five-under-par 67. Moon, Park Sang-Hyun and Kim Hyung-Sung shared the first-day lead, all scoring 34 in the first nine holes at Namseoul Country Club in the OneAsia event.  Another Korean, Hong Soon-Sang finished just off the lead with 68. Australian Michael Sim and Koreans Kim Byung-Jun and Kim Bio came in next with 69s. Unheralded Moon triumphed last year for the first victory of his career.