In the area of Rimhung-dong, the group found out parts of building site in Juche 80 (1991) and 1993, two wells (Wells Nos.1 and 2) in June 2017 and one underground structure built with bricks and pieces of tiles and earthenware and many other relics around it in March 2020. Among the relics are broken tiles and earthenware estimated to date back to around 1st-3rd century and 4th-5th century, which are the same with remains discovered in the first walled capital of Koguryo and at mausoleums of Koguryo kings in the second capital of Koguryo.

It made a wide-range and in-depth joint research into them with various academic institutions at home and abroad.

According to the radio-carbon dating 14C on wood remains from the well relics by means of accelerator mass spectrometry (AMS), the construction periods of Wells No.1 and 2 are proven to be 428-605 and 252-396 respectively and the retirement period of Well No. 1 is 583-656. With building materials, construction method and discovered remains taken into consideration, scholars believe that Well No.2 and the building site had been used by Koguryo people from the 3rd century to the early 5th century.

And Koguryo residential district, an important regional stronghold in the period from the first century to the early 5th century, was unearthed in the Rimhung-dong area for the first time. This makes it possible to prove that Pyongyang was a territory of Koguryo after the first century.

Meanwhile, the research group succeeded in restoring paduk board with 17 broken pieces of stones discovered at Well No.1. The restored paduk board with 19 lines and five starting points in one line shows that the paduk board of Koguryo is the earliest one in the world.

Broken pieces of a large iron pot from Well No.1 and fine-toothed bamboo comb and other relics from Well No.2 go to show the high level of the Koguryo culture at that time.

The Archaeology Society of the DPRK estimated the academic significance of Koguryo relics and remains unearthed in the Rimhung-dong area.

Rimhungdong Koguryo Wells Nos.1 and 2 were listed as preservation relics Nos.1816 and 1817.