Ishima Densetsu Corporation failed to prepare a contract document and allowed some subcontractors to perform work on a project ordered by Wakayama Prefecture, in violation of Article 19, Paragraph 1 of the Building Business Act (Act No. 100 of 1949). Additionally, the company did not display the construction system diagram required by Article 24-8, Paragraph 4 of the Building Business Act, as applied by Article 15, Paragraph 1 of the Act on Proper Promotion of Bidding and Contracting for Public Works, in a visible location at the construction site accessible to workers and the public. Furthermore, the company failed to display the signage required by Article 40 of the Building Business Act at the construction site. These actions are recognized as violations of Article 28, Paragraph 1 of the Building Business Act.