Donald Kirk, in Asia Times, delivers a guide to the likely flashpoints on land and sea.

In the duel between North and South Korea, the question now is who will pull the trigger first? The answer may be neither, but don’t count on it. The dueling now focuses on two quite different flashpoints.

The first is the West or Yellow Sea, where North Korea has vowed to open fire against any South Korean vessel intruding in its waters.

One issue there is how to define which waters are North Korean. The North refuses to recognize the Northern Limit Line, set by the United Nations Command after the Korean War (1950-1953) and challenged by North Korea in bloody gun battles in June 1999 and June 2002. A North Korean boat was sunk in the former incident, killing at least 40 sailors on board. Six sailors died on a South Korean patrol boat in the second battle.

It’s almost June again, the height of the crabbing season in the fish-rich seas and the month when the North is most likely to threaten South Korea’s defense of the line, including islands wrested from North Korean troops in the Korean War. …

If the Yellow Sea is an obvious battleground, however, almost anywhere along the 248-kilometer-long demilitarized zone that’s divided the Korean peninsula since the end of the Korean War could erupt in gunfire. That’s possible quite soon if South Korea makes good on its notion of switching on mega-loudspeakers capable of spewing forth propaganda for the benefit of tens of thousands of North Korean soldiers within shooting distance.

North Korea has said it will respond to the verbal volleys with live fire targeting the loudspeakers. The North Koreans presumably know where they are since they used to shout out the propaganda until both sides agreed to stop the shouting six years ago. That was at the height of the decade of the “Sunshine” policy of North-South reconciliation initiated by the late president, Kim Dae-jung, in 1998.

South Korea’s conservative president, Lee Myung-bak, has turned the clock back on Sunshine since his inauguration a decade later, in 2008. This week he suspended North-South trade, cut off most humanitarian aid, barred South Koreans from visiting the North and opened a global diplomatic offensive in which he’s trying to get the rest of the world, notably China, to go along with condemnation of North Korea and strengthened sanctions.

The diplomatic campaign won’t upset the North Koreans nearly as much, however, as propaganda falling on the ears of their own troops. Lee faces a serious test of nerve. Will he dare order the loudspeakers to blast away knowing the North Koreans may take potshots at them?

And if the North Koreans do fire, will South Korean gunners fire back at the North Korean positions? There’s no telling when the shooting would stop, or whether North Korean troops would try to challenge the South Koreans on the ground.