Sorry for (mostly) copy and paste of the links summarized in the similar question thread.

I mentioned albeit briefly for a while ago in When did Asia learned about "the discovery of America" and how much did they knew about it? that the trading networks of Ainu people from the 13th to 15th centuries who mainly resided in Hokkaido and Sakhalin did not seem to extent beyond the Northern Kuril Islands.

The trace of the Ainu material culture firstly reached only in the southernmost Kamchatka Peninsula in the end of the 15th century.

The Ainu people also had a contact with the Mongolian local government in Lower Amur river, so I suppose [the limitation of] their knowledge on north-easternmost part of Eurasia largely also defined the knowledge of the Mongols (Yuan Dynasty) as well as the Chinese (Ming Dynasty) there. I'd also strongly recommend to check how much of the modern russian far east did the chinese explore?'s answer by /u/_dk