Death Note 23 Day rule? Okay, first read this rule:


  In the Death Note, you cannot set the death date longer than the victim’s original life span. Even if the victim’s death is set in the Death Note beyond his/her original life span, the victim will die before the set time.


So that means if you wrote something like John zeurtö dies peacefully in the year 2315, that wouldn't work because this date is beyond his lifespan. But that would mean, if you wrote a date thats within his actual lifespan, that would work.

But now, there's this 23 day rule.


  The Death Note can only operate within 23 days (in the human calendar). This is called the 23 day rule.


So, could the first example work?
The rules together means the following.

Assume I am dying of a fatal disease and expected to die in 14 days. If I would write that I would die of sexual exhaustion in 21 days, I would still die of the original disease in 14 days before the book can come into effect assuming the cause of death is reasonable.

If I put that someone will die in 24 days of "insert horrific image here", it will not occur as stated.  When I remember that rule tommorrow and write that you will die of the same thing on that date... well... it will not be fun to be you.  If you want to avoid that after reading the death note, I guess you can kill yourself and the deathnote will not stop you as that is the end of your normal lifespan.  Note: you should have brought a pen so you can edit the entry.  That works.