Dangerous Kim Jong-un's Nuke Domino Effect



Hi , look at above picture. Is it possible to have nuke domino effect by Kim jong-un?
South Korea president Park Geunhye warned on nuclear domino dffect, especially by  North Korea's bomb test . Okey Dokey.  Then, by whom?  
It may be from Japan. You are right. There is high possibility that Japan would start to arm itself with nuclear weapons.  Reportedly Japnan has 45tons of plutonium which could make 5000 nuke bomb and hi-tech. Now Japan is under threat by China while they have had conflict over Senkaku Islands.
If Kim Jong-un take and succeed the 4th nuke test, will it be possible for Japan to refrain itself from the temptation of developing nuclear weapons?  No, I don't think so. 
Additionally, Japan is located within the range of NK's long missile firing and they have the cause to get armed by nuke weapons.
Going one more step, if Japan got armed itself with nuclear weapons , then what would Taiwan and South Korea do next?  Both countries also had the experience of developing nuke weapon.
In case of the situation which Taiwan and South Korea start to develop nuclear bomb to protect themselves from the neighboring threat of North Korea, China and Japan armed with nuke weapons, how can the U.S engage in to block them?  Frankly speaking, it is not easy to hold them.
Let it be there? It might be the trigger for a diaster to the earth.
In this context, the role of China which has the Achilles tendonis of North Korea is very important.
It's a little sorroful, but it depend on China whether the earth will be fallen to ruin or not.