[leeeeech]

The words "long" and "evidence" are gross overstatements, but the claim is trivially true if including the Asian origin in "contact". While there is no definite proof for extended contact beyond that, there is no final proof to the opposite either.

The basics are easy to look up. There is plenty of time for exchange in the at least 4000 years of immigration from Asia through the Bering Strait before it almost completely submerged at a time when the first civilizations already emerged, among them chinese.

Still though: Mezo America is far from there in time and space; Grid layout is kind of natural, because only a few space filling polygons exist; The linguistic evidence is very weak at the very least because of the time span, isolation, the lack of written records and corruption of oral tradition.

The search space is huge. A few attractive artifacts may just be noise in the signal. All it takes to satisfy the claim beyond the initial exchange is a single successful explorer.