1) Giving instructions 2) Instructive 3) Mandatory 
Panorama shot of the Hiroshima Peace Memorial, commonly known as the Atomic Bomb Dome, is part of the Hiroshima Peace Memorial Park and was designated a UNESCO World Heritage Site in 1996. The Aioi Bridge, seen at the left side of the image, was the original target of the atomic bombing on August 6, 1945. ...
concerning rules of conduct, laws or precepts
• (a.) Containing or giving precepts; of the nature of precepts; didactic; as, the preceptive parts of the Scriptures.
Pre·cep'tive adjective [ Latin praeceptivus .] Containing or giving precepts; of the nature of precepts; didactic; as, the preceptive parts of the Scriptures. « The lesson given us here is preceptive to us.» L'Estrange. 
of the nature of or expressing a precept; mandatory. · giving instructions; instructive.