The land mine explosions that injured South Korean soldiers in the Demilitarized Zone (DMZ) last month have focused attention on the inter-Korean boundary line and raised the question of whether North Korea deliberately buried its mines south of that border.

But the incident has also left many officials and observers asking an even more fundamental question: Why is the boundary between the two Koreas unmarked in the first place?

There is no fence on the Military Demarcation Line (MDL) in the DMZ, and the markers installed after the signing of the 1953 Armistice Agreement have mostly