This study intended to look into changes in the trade networks of Geumgwan-Gaya by analysis of the iron ingots excavated as burial goods from the 4th ~ 6th century ancient tombs in the areas of Nakdonggang River the southeast coast, and identify the scope and aspects of the interactions in the Geumgwan-Gaya Federation through it. First, this study analyzed the iron ingots buried in the ancient tombs in the areas of the southern coast and the lower Nakdonggang River by the forms and organized the changes in the shape of the iron ingots divided into periods ofⅠ ~ Ⅸ stages through the relics excavated together. Next, this study organized the buried aspects of those iron ingots by the hierarchy through the size of the tombs, and the burial goods of ironware and earthenware. Taking over the form of the plate-shaped iron ax in the middle of the 3rd century, the iron ingots were buried like a rail in the tombs for the highest hierarchy starting from the end of the 3rd century in the areas of Daeseongdong, Gimhae and Bokcheon-dong, Busan, where were the center of Geumgwan- Gaya. Starting from the middle of the 4th century to the early of the 5th century it shows the strong trend in the shape of the iron ingots being standardized into the symmetrical arc from of 15~22cm(ⅢBc), which are buried in bundles concentratedly inside the middle of the tombs for the early and lower hierarchy, and the number of tombs with hierarchy is increasing even in the small and medium-sized ancient tombs as well. After the middle of the 5th century, the symmetrical ones in the 10~15cm with arc blade and narrow-width (ⅣBc) are increased, and the iron ingots are buried also in the tombs for the lower hierarchy out of the small and medium-sized tombs. Together with the iron ingots, it shows noticeable burial goods of iron smelting tools such as hammers, anvils and tongs, evidencing that the hierarchy of ironware making becomes diversified. This shows that the iron ingots, that had been buried as a wealth symbol in the large-sized tombs for the highest hierarchy since the end of the 3rd century and the beginning of the 4th century, were buried in the small and middle-sized tombs for the highest hierarchy who formed the craftman networks in iron production by small regional unit in the middle and latter half of the 4th century, and they took in charge of the production and distribution of the iron ingots for the highest hierarchy of the Daeseong-dong ancient tombs under the control of them. However, after the 5th century, it became possible of iron production function by towns & villages of political structures in small unit areas. Since then, Geumgwan-Gaya, which lost its foreign trade routes, was transformed into a form of trade & distribution between the political structures in the inland area of the Nakdonggang River and the ones in small areas through the southern coast. Thus, those political structures in the small unit areas of the lower Nakdonggang River and the southern coast continued to maintain as the regional political structures of Geumgwan-Gaya even after the southern conquest by Goguryeo Kingdom, while interacting on equally basis as the trade ports of the later Geumgwan-Gaya.
Abu Muslim qala: an iron-production site along Central Asia's medieval north–south trade routes
