I dont know what the truth is about this era. I've been told the Japanse historians dont publish much about the archeological evidence, or of any documents from that century. They stick to the Japanese tradition, that Japan has never been conquored and the Emperors ancestral line has never been broken.

Perhaps, perhaps not. The Koreans claimed otherwise long ago.

I think trying to learn about East Asian history can be pain in the ass.  You get 'Version A' from China, 'Version B' from Japan, and 'Version C' from Korea.  A big contributing factor is that there is a sandbox known as 'national history' and another sandbox known as 'world history' (or 'western' and 'eastern' histories, whatever).  The 'national history' part is the worst offender as it is prone to exaggerations (playing up past achievements while playing down past disasters) and lack of line separating facts from myths.

 

I think the Japanese treatment of the Mongol invasion is rather mild, compared to their treatment of ancient time contemporary to Korea's three-kingdom period.  (This is a big deal, as significant movements of people, technology, and culture have taken place at and before that era.)

 

As for the Mongols and no Kamikaze ...

 

I am not confident about the possibility of Mongol successes in Japan, apart from winning opening battles.  Problems:

 

1.  There were no central government to topple.  Instead, the Mongols and allied forces would have had to take on one Daimyo at a time.

 

2.  The biggest problem would have been in the realm of logistics.  Conquering and garrison forces  would have required steady shipments of food and supplies from the continent.  Not something that could have been done year-around, once typhoon seasons and possibility of bad harvests were taken into consideration.  Even without the two catastrophic Kamikazes, the sheer cost of assembling vast invasion fleet twice would have had played havoc in the Yuan treasury.

 

3.  The most realistic scenario would have been to make quick raids into Japan, plunder as much as possible, then get the hell out.  Perhaps repeat this sporadically as opportunities arise in the future.  This minimizes the cost of sustained battles and occupation.

 

*****

Off-topic:  For comparative purposes, let's take a quick look at Korea's invasion of Tsushima Island during its early Chosun Dynasty.

 

The central government decided to stop recurring Japanese piracy by going after their base of operation:  the Tsushima Island.  They sent something like 10000 troops and sailors.  At first, the government thought of annexing that island.  But they changed their mind once the cost of occupation were taken into account.   They were content with accepting token surrender then expanding cross-strait trade between Korea and the Tsushima.  (There was also a practical reason for keeping Tsushima independent.  It also acted as the buffer between Korea and Japan.)