Death Note Rules are what make the usage of Death Note easy.
Death Note is an extraordinary magical notebook used by the god of death, Shinigami, to extend their life span.
One of the basic Death Note Rules was that “the human whose name is written in the Death Note shall die”.
Since everything in the universe has certain rules to be followed, the Death Note also has certain rules for its human owners.
1. The Death Must be Logical

All deaths caused by a death note are supposed to make reasonable sense.
For example, if a person is in Japan, he/she cannot be killed in Paris in one hour.
The cause of death must not be extravagant or humanly impossible.
Death should then be physically and circumstantially possible; otherwise, the person will not die.
This was one of those Death Note rules that Light tested in order to take advantage of it.
2. Image of the Person and Spelling of his/her Name- The Two Important Death Note Rules
A person whose name is written in the death note dies after the owner of the death note has a vision of that person in his/her head.
The memory of the person’s face in the imagination of the writer is important.
As it prevents the death of persons of the same name.
Often, the person whose name has been incorrectly written or misspelled more than four times will not be affected by the Death Note.
This spell check is one of those death note rules that have the greatest risk of causing trouble to Light Yagami as the Death Note will no longer be able to kill the person.
This rule can also be considered as one of the worst death note rules.
If the owner misspelled the name of the person to be killed intentionally for the fourth time, the owner of the Death Note die.
3. Cause of the Death

If the cause of death of a person is not specified, the person will die of a heart attack and if the cause of death is written within 40 seconds of writing his/her name, the death will occur.
As stated in the above death note rules, the cause of death must be logical.
After writing the cause of death, the writer would have 6 minutes and 40 seconds to write the specifics of the death to be caused.
4. The Death Note User cannot extend his/her own Life Span, Shinigami Eyes.
Death Note has the ability to kill humans. But the owner cannot have a prolonged life span.
However, receiving it shortens the life span of the human user somewhat. The person may also obtain the Shinigami eyes.
It makes the owner of the death note more powerful by giving half their life span to the god of death.
Shinigami eyes allow the owner to see the name and life span of every human only by pointing at his/her face.
Light Yagami didn’t want to cut his own life short, so he didn’t take the eyes of Shinigami.
However, Misa Amane, the second Kira had the eyes of Shinigami. She took them to discover Light Yagami, the first Kira.
5. A Name Cannot Be Erased

If the name of the person is written in the death note, he or she shall die.
The name cannot be erased, and even though the paper is ripped, the person will still lose his or her life.
Therefore, before writing a name, the user should be confident that he/she wants to kill a particular human.