It has long been suggested that the Ainu may be white caucasians, descended either from seafarers or Europeans who migrated eastward across Asia. There are also disputed traces of early white people in parts of China.
That certainly is suggested by the faces in the photo.
I have not kept up with this theory in recent years, but it would be interesting to know what DNA testing suggests about their genetic background.
Quite possibly. They are certainly light-skinned, as the picture shows. Some have red or brown hair and green or blue eyes. 
Some experts think they are related to Kennewick Man.
There are also disputed traces of early white people in parts of China.
Those, I believe, are the Tocharians (AKA Yuezhi), who are thought to have spoken an Indo-European language distantly related to Latin.
I don't think the Ainu language is Indo-European.
-ccm
“It has long been suggested that the Ainu may be white caucasians,”
That’s what I’d read as well. The American Indian is Asian, the Ainu is Caucasian.