Christopher I. Beckwith, applying his own Middle Chinese readings, claims that almost all of the words have Japonic cognates. He takes this as the language of Goguryeo, which he considers a relative of Japanese in a family he calls Japanese-Koguryoic. He suggests that the family was located in western Liaoning in the 4th century BC, with one group (identified with the Yayoi culture) travelling by sea to southern Korea and Kyushu, others migrating into eastern Manchuria and northern Korea, and others by sea to the Ryukyu Islands. In a review for "Korean Studies", Thomas Pellard criticizes Beckwith's linguistic analysis for the "ad hoc" nature of his Chinese reconstructions, for his handling of Japonic material and for hasty rejection of possible cognates in other languages. Another review by historian Mark Byington casts doubt on Beckwith's interpretation of the documentary references on which his migration theory is based.