The purpose of artifacts with intersecting holes remains unclear to this day, but apparently they can be classified as items used for industrial purposes. Some researchers also believe that they could perform a certain ritual function.
These artifacts come in rectangular and cubic shapes. Some items have one or all sides adorned with decorative patterns, which were incised after thermal treatment. Many of them have traces of smoke in the holes.
Similar items are also found at archaeological sites of other Bohai culture monuments in Primorsky Krai. They are often found in pit furnaces (depressions in the ground used to light a fire, over which pottery furnaces are set up), amidst slag and ash, in places of metallurgical production.
These artifacts are made of clay, although several specimens are made of pumice, a porous volcanic glass that was formed as a result of the release of gasses during rapid cooling of acidic and intermediate lavas.
Until recently, there were few hypotheses about the purpose of these items. Some researchers believed that they were used by shamans for ritual purposes, as supports for their staffs. Others referred to them as regulators for tent poles. Still others suggested that they might have been used for better air circulation during metal smelting and pottery firing. Chinese archaeologists classify them as items of uncertain purpose.
Similar rectangular wooden objects are on display in one of the museums of Japan in Niigata Prefecture, near the city of Sendai. According to the Japanese, these objects were used with ropes threaded through the holes to adjust the height of a kettle, which was suspended and secured through a perpendicular hole above the hearth.
The smoke stains and wear marks around the two parallel holes on the Bohai artifacts likely indicate their use as kettle regulators above the hearth. Due to the stresses during handling, objects often broke along the line of the vertical hole.
The collection includes an item discovered in the Spassky District of Primorsky Krai by the archaeologist and researcher of the ancient history of the Spassky and Chernigov Districts, Fyodor Pavlovich Trigub.
