I love Knox's Decalogue :D

I like detective. And I plant Knox's Decalogue in my detective mind :D ...
There are 10 rules on Knox's Decalogue :D .. :

Knox's 1st

It is forbidden for the culprit to be anyone not mentioned in the early part of the story.

Knox's 2nd

It is forbidden for supernatural agencies to be employed as a detective technique.

Knox's 3rd

It is forbidden for hidden passages to exist.

Knox's 4th

It is forbidden for unknown drugs or hard to understand scientific devices to be used.

Knox's 5th

It is forbidden for stereotypical minorities to assist or hinder the detective beyond providing their own conclusions and interpretations, or for said minorities to be the culprit.

Knox's 6th

It is forbidden for accident or intuition to be employed as a detective technique.

Knox's 7th

It is forbidden for the detective to be the culprit.

Knox's 8th

It is forbidden for the case to be resolved with clues that are not presented.

Knox's 9th

It is permitted for observers to let their own conclusions and interpretations be heard.

Knox's 10th

It is forbidden for a character to disguise themselves as another without any clues.