Gaya constructed wooden tombs since the later period BC. Since the late 2nd century to the 4th century, wooden tombs were used as the main type of burial. From the 5th century to the first half of 6th century when Gaya collapsed, stone tombs had been constructed. The stone chamber tombs were introduced from the Silla, Baekje, and Japanese Islands in the 6th century. The change of tomb types and funeral rituals are associated with the establishment, development and decline of Gaya. The appearance of different tomb types and its changes during 600 years show the Gaya’s history of exchange with the surrounding countries. It is important proof to understand international relations of that time. Along with the change of the tomb types, relics excavated at the tumuli also show the truth of Gaya culture. Relics found in Gaya tumuli are evidence of actual life of Gaya people and international exchange among surrounding countries such as China and Japan. The relics help to infer the international relations at that time. Moreover, it became possible to understand the afterlife thoughts of Gaya people through the rituals, construction of the tumuli, relics, sacrificial burial of human and animal.
Gimhae Daeseong-dong Tumuli was composed in the earlier period and 219 tombs were investigated until now. Also, around 69 tombs are wooden outer-coffin tombs that seem to be the tombs of the elite class. The wooden coffin tombs of 1st~2nd century were mainly constructed in the slopes or the flatland surrounding the Aeguji hills. The wooden outer- coffin tombs (Daeseong-dong No. 29) that appeared in the late 3rd century were built on the upper part of the hill and many relics that seem to be traded from China and Japan were found along with iron ingots and ironwork.
There are 17 mounded tombs among 127 mounded tombs that have been investigated in the Haman Marisan Tumuli. The wooden coffin tombs and wooden outer-coffin tombs were constructed around the slopes of the northern part of the hill, and after the 5th century high- mound tombs were constructed to the southern part of the hill. The stone-lined tombs in a long and slender form have unique structure of crossbeam facility and four walls to raise structural stability. Iron bard, horse helmet, and iron made horse gear and sword with ring pommel were found. The high degree of formalized human sacrificial burial are observed.
Among the 28 mounded tombs of Hapcheon Okjeon Tumuli, 10 mounded tombs have been investigated until now. The wood coffin tombs were built in the slope of the eastern part of the hill and then the high-mound tombs were composed in the central part of the hill. The main tomb type of Okjeon Tumuli is the large-scale wood-coffin tombs. The stone-lined tombs with vertical entrance and the stone chamber tombs with horizontal entrance appeared later. The structure of the wood-coffin tombs is connected with the construction method of Silla’s stone mound tombs, and the stone chamber tombs with horizontal entrance were affected by Baekje. The relics found in the tombs show the international exchange of the time. The Yongbongmun(dragon and phoenix decoration) sword with ring pommel and bronze lidded bowl are deeply relative to the Baekje, and the gilt bronze crown reflects the exchange with Silla while the armor reflects the exchange with Japan. Also, the Roman Glass show dynamism of Gaya that participated in the international trade at the time where it seems like the Roman Glass was brought in to the Okjeon Tumuli from western areas by way of China and Silla.
Wood coffin tombs were not investigated at the Goryeong Jisan-dong Tumuli, but transition from wood outer-coffin tomb to stone lined tomb was investigated (Jisan-dong No. 73). Large mound was constructed on the main burial part of the tombs. There is a separate space within the reinforced soil of main burial mound to place sacrificial attendants. It is the original form of the accessory chamber for sacrificial burials. The main tomb type of the elite class is stone- lined tombs with vertical entrance. It contains many artifacts which demonstrate authority of elite class, such as gilt bronze crown, earings, decorated horse gear, and other relics. Jisan- dong tomb No. 44 shows that great effort and money were invested in constructing the tumuli where more than 40 sacrificial attendants have been buried. Goryeong Jisan-dong Tumuli is one of the greatest and biggest tumuli among the Gaya Tumuli where there are more than 10,000 small and medium tombs and over 700 mounded tombs.
It is known that there are around 15 mounded tombs in Goseong Songhak-dong Tumuli and 2 have been investigated until now. Songhak-dong Tumuli shows tradition of ‘mound burial’. The main feature of mound burial is making several main burial chambers gradually on big mound. For example, Songhak-dong tomb no. 1 was constructed in late-5th century. It is composed of 3 mounds(tomb no. 1A, 1B, 1C). There are several different form and structure of burial chambers on the tops of each mounds.
There are around 320 tombs in Changnyeon Gyo-dong and Songhyeon-dong Tumuli. Among these tombs, around 20 mounded tombs were investigated. However, wood coffin tombs and wood outer-coffin tombs have not been found. The main tomb type of elite class are stone-lined tombs with vertical entrance and stone chamber tombs with horizontal corridor. The large-scale stone chamber tomb with horizontal entrance(Gyo-dong Tomb No. 4) have been constructed from the mid of the 5th century.
In Changnyeong Gyo-dong and Songhyeon-dong Tumuli, a burial mound has only one main burial chamber without any accessory compartments. Therefore, sacrificial attendants were layed within main burial chamber. The excavated artifacts such as decorated horse gear, gilt bronze crown, and belt ornament show exchange between Gaya and Japan, Silla, Baekje.
Namwon Yugok-ri and Durak-ri Tumuli has over 40 mounded tombs and 6 were investigated. There were no signs of wood coffin tombs. The Durak-ri Tomb no.32 is constructed in the late 5th century. It is stone lined tomb and Chinese bronze mirror, Baekje gilt bronze shoes, Daegaya earthenware, horse gear, armor were excavated. Durak-ri Tomb no. 2, constructed after the mid-6th century is a stone chamber tomb with horizontal entrance which was affected by Baekje.