North Korean Bombardment and "Deterrence"

The North Korean Army bombarded a South Korean island, reportedly with their 120mm field guns, on 23 November. This was the first act of its kind since the ceasefire of 1953. No doubt it is condemnable. Joint US-South Korean military exercises are being held in the sea southwest of the Korean Peninsula from 28 to 1 December. For this purpose the US dispatched a nuclear aircraft carrier George Washington, together with a cruiser capable of launching a Tomahawk missile and three destroyers, all from their naval bases in Japan.
There was a crisis in the early 1990s threatening a Second Korean War. Nobody at this time is prepared for a war, but the tension should be dissipated as quickly as possible. If Japan establishes diplomatic relations with the North, it would greatly serve the purpose. There is nothing to prevent it. Great many UN members have already relations with DPRK. Yes, there are outstanding issues between the two, but having relations would make it much easier to negotiate the matters. The bombardment has strengthened fear and encouraged demand for more deterrence. But establishing official relations would be by far the best deterrence.