The northern part of Ok-jŭ was called Puk Ok-jŭ or “North Ok-jŭ.” The customs of these people were the same as those of the south except for some differences caused by the proximity of the Eum-nu tribe to the north, who were the Apaches of Korea. Every year these fierce people made a descent upon the villages of the peaceful Ok-jŭ, sweeping everything before them. So regular were these incursions that the Ok-jŭ people used to migrate to the mountains every summer, where they lived in caves as best they could, returning to their homes in the late autumn. The cold of winter held their enemies in check. We are told that a Chinese envoy once penetrated these remote regions. He asked “Are there any people living beyond this sea?” (meaning the Japan Sea.) They replied “Sometimes when we go out to fish and a tempest strikes us we are driven ten days toward the east until we reach islands where men live whose language is strange and whose custom it is each summer to drown a young girl in the sea.” Another said “Once some clothes floated here which were like ours except that the sleeves were as long as the height of a man.” Another said “A boat once drifted here containing a man with a double face, one above the other. We could not understand his speech and as he refused to eat he soon expired.” The tribe of Ok-jŭ was finally absorbed in Ko-gu-ryŭ in the fourth year of King T’ă-jo Wang. The Eum-nu tribe did not belong to Korea proper but as its territory was adjacent to Korea a word may not be out of place. It was originally called Suk-sin. It was north of Ok-jŭ and stretched from the Tu-man river away north to the vicinity of the Amur. Its most famous mountain was Pul-ham San, It is said to have been a thousand _li_ to the north-east of Pu-yŭ. The country was mountainous and there were no cart roads. The various cereals were grown, as well as hemp.