over 400 meters in length. By the late Kofun period, the distinctive burial chambers, originally used by the ruling elite, were also built for commoners. The biggest kofun are believed to be the tombs of emperors like Emperor Ōjin (応神天皇 Ōjin Tennō) and Emperor Nintoku (仁徳天皇 Nintoku Tennō). Kofun are also classified according to whether the entrance to the stone burial chamber is vertical (縦穴 tate-ana) or horizontal (横穴 yoko-ana). Immigrants in early Japan Japan of the Kofun period was very receptive to influence from China. Chinese and Korean immigrants played an important role in introducing elements of Chinese culture to early Japan. Yamato links to the mainland and the Liu Song Dynasty in 425 and 478 were facilitated by the maritime knowledge and diplomatic connections of China and the Three Kingdoms of the Korean peninsula, especially Baekje. Many important figures were immigrants from East Asia. Yamato Imperial Court officially edited the Shinsen Shōjiroku in 815 as a directory of aristocrats which lists 1182 names of clans which were in Kinai area, it lists a number of clans from the Han China, Silla, Baekje and Goguryeo. According to the directory, 174 clans have roots in China, 120 clans have roots in Baekje, 48 clans have roots in Goguryeo, 17 clans have roots in Silla, then 9 clans have roots in Gaya of the Korean peninsula. The Azumi people were a warrior tribe from northern Kyushu. They were extremely skilled seafarers. The Azumi gained early contact with the Yamato Court and provided maritime trade links and influenced the Yamato Court's military and diplomatic approach in the seas. Thus the Japanese imperial government employed them as their naval force from the 3rd to 5th centuries. Certain experts regard the Azumi as "the oldest known maritime force of [Japan's] emerging imperial state." Some Japanese historians think they were of Austronesian origin and related to the Hayato people who lived in southern Kyushu. The Yamato Court questioned their loyalty and banished them sometime before the 7th century. Kofun society The Kofun period was a critical stage in Japan's evolution toward a more cohesive and recognized state. This society was most developed in the Kansai Region and the easternmost part of the Inland Sea. Japan's rulers of the time even petitioned the Chinese court for confirmation of royal titles. The Yamato polity, which emerged by the late 5th century, was distinguished by powerful great clans