Why did the Mongols decide to attack the Hakata Bay area during their attempted invasions of Japan in 1274 and 1281?

by SenorLos

Just now I watched this video about the attempted Mongol invasions of Japan.

I guess that Japan with its foresty mouintains would be difficult to invade for the Mongols who would probably favor open plains. So finding a good spot to land would be especially difficult for them.
But why did the Mongols attack the Hakata Bay area with its fortifications twice? To me it seems to be a particularly bad spot. More so in 1281, after the Japanese enhanced their fortifications and conveniently(?) guarded the area with an army.

y_sengaku

Though it would be definitely better to wait for responses either from the Mongol History or Japanese Medieval Historians, I just complement some brief historical background around two Mongol invasion attempts as well as some facts on the Japanese-Chinese(-Korean) sea trade across the East China Sea in the 13th century that I assume relatively less known out of East Asia.

Put it briefly, contrary to OP's supposition, the majority of Japanese scholars tend to point out the general overestimation of the Mongols as a sea power at that phase (ca. 1280), and regard the NW Kyushu around Hakata Bay as an only realistic destination of the fleet. Their reasonings are as following:

  • As you can see the linked map (though I don't recommend NG's not so academic linked article for this topic so much), the main force of the Mongol invasion fleet departed not directly from China, but from now Masan in SE Korea in both attempts. In addition to the Mongols, the Koreans constitute considerable part of the invasion army especially for the first invasion (1274).
  • The first invasion attempt of the Mongols to Japan in 1274 was in fact almost the first large-scale naval operation in the Mongol history, and the Mongols themselves definitely lacked enough knowledge of the sea route across the East Asia. So, the fleet had to rely on the Korean sailors those who were originally sailor of the merchant ships between Korea and Northern Kyushu like Hakata or Dazaifu for the navigation. In spite of their navigation guide for this shortest route between Korean Peninsula and Northern Kyushu, the first invasion did not work so well. If the fleet tried to attack other than famous port region like Hakata Bay, the result would have been more disastrous one.
  • As for the second invasion, some ex-Sung fleet under the leadership of Chinese General Fan Wenhu also participated in the invasion army, but they had to depart far from Southern China and neither the Chinese did not know much about Japan except for the famous trade route to Northern Kyushu like Hakata Bay. It was also a long voyage from Southern China to Japan without any stopping at ports, so neither of the invasion fleet did not have much choice of landing place.

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