Unpredictable, irrational DPRK

A very short history of the DPRK and some possible rational why the unpredictable country that seems strangely predictable is behaving so irrationally is online at PBS. Some parts may be quibble worthy* (was Kim Il-sung really an anti-Japanese guerrilla or could that be part or all myth?), but it might give some insight:

North Koreans have long felt threatened by American nuclear weapons, and sought protection under the Soviet nuclear umbrella by signing a mutual defense treaty with the USSR in 1961. But North Korea does not have a lot of trust in Russia or China either... ...it is surrounded by enemies or, at best, untrustworthy "friends"...

...This modern state of insecurity is built upon an older history of colonialism and traditional isolation to create an attitude of profound suspicion of the outside world...PBS

*Others may argue that Japanese colonialism of Korea was not really colonialism among other things.