During the Bronze Age, jar coffin tombs closely related with the Songgukri culture are densely concentrated in the lower reaches of the Geum River. 65% of jar coffin tombs discovered in the southern part of Korean Peninsula are located in this region and a majority of pottery used as jar coffin is the Songgukri type pottery. Outside the lower reaches of the Geum River, even in Hoseo area where the river runs through, jar coffin tombs are occasionally discovered. Either an upright rimmed pottery or a deep bowl was used as a coffin rather than a very specific Songgukri type pottery. Compared with Hoseo area, there are relatively less jar coffin tombs in Honam area with a high proportion of non-Songgukri type potteries used as jar coffins. In Yeongnam area, only three jar coffin tombs of the Songgukri type were found. Thus the influence of the Songgukri culture was very limited in the area. Outside the lower reaches of the Geum River, it is noticeable that the an upright-rimmed pottery or a deep bowl, not a Songgkri type pottery with an outspread rim, for a coffin had increased. Considering the fact that the upright-rimmed potteries tend to be found in the elongated rectangular outlined dwelling pits in the preceded Early Bronze Age period, some scholars assumed that such jar coffin tombs were constructed before the period of the Songgukri culture. However, common use of potteries with upright rims or deep bowls during the Songgukri culture, rules out that assumption, and it is suggested that determination for the date of construction must be based on considering general contexts of
the sites rather than the sole analysis of the pottery shape and typological seriation. A majority of the upright-rimmed potteries or deep bowls as jar coffins are found in either Hoseo or Honam area, which are located outside the lower reaches of the Geum River. Given the accepted assumption that the Songgukri culture had spread to the adjacent
areas from the lower reaches of the Geum River, the construction date for coffin jars with upright rims or deep bowl coffins could belong to the expansion phase rather than the early emergence phase of the Songgukri culture. Thus, these jar coffins were local variations while the Songgukri culture had been expanding. What caused such variations reflecting the selective adoption of the Songgukri culture by local people? Jar coffins using the original Songgukri type potteries to bury the deceased, are quite rare outside the mid reaches of the Geum River. Even if a mortuary
practice to use jar coffins had been adopted, it seems that there was no strict regulation to use the Songgukri type pottery only in this region.