More like the Indians, more specifically the early Indo-European. You can trace the migration of Indo-European by language groups. Sanskrit was carried from India to Mesopotamia, into the central step, to the northern caucuses and even as far as the eastern step and into Manchuria.

It's possible that this particular particle was transferred from central step people like the scythian to eastern tribes of the xiongnu who eventually settled in Southern Korea, leading to the yayoi migration to Japan.