"Both the Hokkaido and Sakhalin Ainu had been using metal goods traded from the Japanese and Chinese so long that they had completely forgotten that their ancestors once used pottery.
The Sakhalin Ainu, too, practiced seasonal migration and their winter houses were pit houses as were those of the Kurile Ainu" (Ohnuki-Tierney, 1974).
I found it funny that the Ainu had forgotten that their ancestors used pottery at one point.
1974 Another Look at the Ainu – A Preliminary Report. The University of Wisconsin Press (11): 189-195.