Japan has a lost tribe or some such in their very ancient past that supposedly crossed the seas. The Zuni people of modern New Mexico speak a language that has a lot of similarities (way above pure chance) to Japanese and further the Zuni are mostly type B blood type (the most common in Japan) as opposed to type A (which is the most common in North America).

Solid evidence of Japan in Latin America during the 16th century.

And there was sizeable Chinese trade and travel in the 17th

Sunrise Invasion Gang.