Later from August 10 through September 15 in 1992 the Kunaicho Shoryoubu (the Library of Kunaicho) conducted closure works of an opening, along with an additional simple measurement investigation and after the work and research they published the written report.
その後1992年8月10日から9月15日まで宮内庁書陵部による開口部の閉塞工事にあわせて簡単な実測調査が行われ、後日報告書が作成、公表された。