Laos: Plain of Jars: cemetery, bodies in big stone jars, wood lids
Korea: Big Onggi pots for fermenting cabbage into kim chee.

Were large containers used for non-fire pickling, to make tough meat & veggies softened?

The jars lie in clusters on the lower foot slopes and mountain ridges of the hills surrounding the central plateau and upland valleys. Several quarry sites have been recorded, usually close to the jar sites. Five rock types have been identified: sandstone, granite, conglomerate, limestone and breccia. The majority of the jars are sandstone. It is assumed that Plain of Jars people used iron chisels to manufacture the jars, although no conclusive evidence for this exists. Regional differences in jar shape have been noted. While the differences in most cases can be attributed to choice and manipulation of rock source, some differences in form (such as variations in the placement of jar apertures) appear to be unique to specific sites.

A cave at Site 1 is a natural limestone formation with an opening to the northwest and two man-made holes at the top. These holes are thought to be chimneys for a crematorium. French geologist and amateur archaeologist Madeleine Colani excavated inside the cave in the early 1930s and found material to support a crematorium theory. Colani also recorded and excavated at twelve Plain of Jars sites and published two volumes with her findings in 1935. Colani concluded that the Plain of Jars was an Iron Age burial site. Inside the jars she found, embedded in black organic soil, coloured glass beads, burnt teeth and bone fragments, sometimes from more than one individual. Around the stone jars, she found human bones, pottery fragments, iron and bronze objects, glass and stone beads, ceramic weights and charcoal. The bone and teeth inside the jars show signs of cremation, while the burials surrounding the jars yield unburnt secondary burial bones.

Plain of Jars – Site One
No further archaeological research was conducted until November 1994, when Professor Eiji Nitta of Kagoshima University and Lao archaeologist Thongsa Sayavongkhamdy surveyed and mapped Site 1. Nitta claimed that the surrounding burial pits were contemporaneous to the jars, as they had been cut into the surface on which the jars had been placed. Nitta believed the jars were symbolic monuments to mark the surrounding burials. He dated the Plain of Jars to the late second or early first millennium BCE based on the burial urn and associated grave goods. Sayavongkhamdy undertook surveys and excavations between 1994 and 1996, supported by the Australian National University.. Sayavongkhamdy and Peter Bellwood interpreted the stone jars as a central person's primary or secondary burial, surrounded by secondary burials of family members. Archaeological data collected during bomb clearance operations supervised by UNESCO archaeologist Julie Van Den Bergh in 2004–2005 and again in 2007 provided similar archaeological results. Like Nitta, Van Den Bergh concluded that the jars and surrounding burials were contemporaneous.

Variations in the practices of cremation inside jars and secondary burial outside jars, as noted by Colani, have proven difficult to explain. The cremated remains seem to mainly belong to adolescents. While the bomb clearance operations did not involve emptying of jars and thus no additional evidence could be gathered, Van Den Bergh claimed that the stone jars initially may have been used to distill the dead bodies and that the cremated remains within the jars represent the most recent phase in the Plain of Jars. The jars with smaller apertures may reflect the diminishing need to place an entire body inside.

The suggestion that the jars, similar to traditional Southeast Asian Royal mortuary practices, functioned as "distilling vessels", was put forward by R. Engelhardt and P. Rogers in 2001. In contemporary funerary practices followed by Thai, Cambodian, and Laotian royalty, the corpse of the deceased is placed into an urn during the early stages of the funeral rites, at which time the soul of deceased is believed to be undergoing gradual transformation from the earthly to the spiritual world. The ritual decomposition is later followed by cremation and secondary burial.

Incidentally, the megalithic Dravidians of South India used giant burial urns called Mudhumakkal Thazhi ('burial-pots-of-the-old-people') or EemaThazhi. These funerary urns were buried with the bodies of the deceased or soon-to-die in a sitting posture, along with their personal goods and ornaments.[4] This practice was in vogue until 200 CE.[5]

The royal burials are across watercourses from the habitation areas in a geographically high, prominent area. Among the Black Thai people who have been in the region at least since the 11th century, the upper classes are cremated in the belief that it will release their spirits to heaven, while commoners are buried, leaving their spirits to remain on Earth.

Colani connected the location of the jars sites to ancient trade routes, in particular with the salt trade. She assumed that salt was a commodity sought after by the Plain of Jars people, which brought traders to the Xiangkhouang Plateau. The Xiangkhouang area is rich in metallic minerals, mainly due to granite intrusions and associated hydrothermal activity.

Two principal iron ore deposits exist in Laos, both in Xiangkhouang. The presence and locations of the numerous jar sites in Xiangkhouang may relate to trading and mining activities. History has shown that Xiangkhouang, at the northern end of the Annamite Range, provides relative easy passage from the north and east to the south and west.