Japan-North Korea Relationship

The readers who have gone through 'North Korean Bombardment and "Deterrence"' last week may have come across at least three questions. Why are the US naval ships based at Japan? What is the constitutional status of those bases? Why does Japan have no diplomatic relations with DPRK? Let me discuss the last one today.
In August 1945, Japan was desperately fighting the powerful Allies. The Potsdam Declaration had already been issued, demanding immediate surrender and threatening to strike with greater force if Japan didn't. Japan didn't, at least not soon enough. If Japan had done so, there would have been no division of the Korean Peninsula, then under the Japanese rule, as the Russians would not have been in the war against Japan then. When the Russians declared war on the side of the Allies, the US forces were not yet in a position to reach the Peninsula easily. The US thereupon decided that the Peninsula should be divided at the 38th Parallel into two occupation zones, to stop the southward advance of the Russian Army and to let them take the surrender of the Japanese troops only north of the line. It had the great advantage of assigning Seoul, the capital and the largest city, to the US. The Parallel was thus not intended to be a boundary. But it soon became one when both the US and Russia brought their own men to their zones and established governments around them. It was in 1948.
When Japan regained her independence in 1952, the Korean War was going on and Japan had already been allied to the US. Between the PRC and Taiwan Japan chose, or was made to choose, Taiwan. Between the two Koreas, South Korea. The Treaty of 1965 normalizing relations of Japan and South Korea says that South Korea is the only lawful government in Korea. Establishing relations with the North would mean, therefore, that Japan will come out of the Cold War legacy in East Asia, and will also overcome her imperial past. It may also, hopefully, help the two Koreas to be united again, peacefully.