罪犯必須是故事開始時出現過的人，但不得是讀者可以追蹤其思想的人。
2 All supernatural or preternatural agencies are ruled out as a matter of course.
偵探不能用超自然的或怪異的偵探方法
3 Not more than one secret room or passage is allowable.
犯罪現場不能有超過壹個秘密房間或通道
4 No hitherto undiscovered poisons may be used, nor any appliance which will need a long scientific explanation at the end.
作案時候，不能使用尚未發明的毒藥，或需要進行深奧的科學解釋的裝置
5 No Chinaman must figure in the story.
不準有中國人出現在故事裏(備註1)
6 No accident must ever help the detective, nor must he ever have an unaccountable intuition which proves to be right.
偵探不得用偶然事件或不負責任的直覺來偵破案件
7 The detective must not himself commit the crime.
偵探不得成為罪犯
8 The detective must not light on any clues which are not instantly produced for the inspection of the reader.
偵探不得根據小說中未向讀者提示過的線索破案
9 The stupid friend of the detective, the Watson, must not conceal any thoughts which pass through his mind; his intelligence must be slightly, but very slightly, below that of the average reader.
偵探的笨蛋朋友，比如華生，必須將其判斷毫無保留地告訴讀者，此人的智力須輕微低於讀者的平均水平。
10 Twin brothers, and doubles generally, must not appear unless we have been duly prepared for them.
小說中如果有雙胞胎或雙重身份的人時，必須提前告訴人們