Why did the mongols fail to conquer japan in 1274 and 1281?

Okay, I have answered this question before, but I'm going to try and avoid giving you the same answer. So, at this time, we all know the very powerful person leading the Mongols at this time, was of course, no other than, Genghis Khan. He had sent an armada to invade Japan, but being in this time when they invaded, it was Typhoon Season in Japan, leaving the waters very unsafe to travel in. What made matters even worse were that the Japanese were actually very intelligent, and were lead by very intelligent Generals. But one of the main geographical factors that lead to the failure of their conquer was that Japan was an archipelago. Japan is the culmination of 4000+ islands, making it very hard for the Mongols to conquer the whole thing, so think of it this way; It would be like invading the Caribbean. The Caribbean consists  of numerous islands, and it's likely to be the Mongols do not know the strength, or numbers of the people in each island, so each time he would invade, it's a risk. 

Italy , germany, austria, japan, and brazil.