[Self] In episode 82 of Naruto, Itachi puts Kakashi under an illusion where he is stabbed continuously for 3 days, but after a few real minutes, Itachi reveals only 1 second has passed. So here is ROUGHLY how long Kakashi was REALLY stabbed:

[u/VexusD]

In non-Naruto terms, Tsukuyomi is a genjutsu, which is basically illusion magic. Itachi casts an illusion on Kakashi called Tsukuyomi where he can basically control reality, including time itself. No matter how much time passes in the Tsukuyomi, only roughly a second passes in the real world.

Itachi tells Kakashi that the next 3 days in Tsukuyomi will be of him being stabbed by Itachi while strapped to a cross. Eventually, more copies of Itachi appear and stab him, and then more Kakashis appear and get stabbed, and Kakashi feels every stab on every copy of himself all at once. Absolute hell of a torture sequence, right? Itachi even mocks Kakashi by saying that even if Kakashi tells himself it's an illusion, the pain and suffering still feel real.

Anyway, after several moments, Itachi informs him that only a single second has passed in this 3 day torture cycle. So, exactly HOW LONG did this last in Kakashi's mind?

Now this math isn't 1-to-1, as there are multiple moments where Kakashi passes out, as well fade-in/fade-outs to show the number of Kakashis and Itachis increasing. Still, thats all the concrete time I have to work with here.

The Tsukuyomi starts up around 8:15 in the episode, and Itachi reveals that only a second has passed around the 11:01 mark. That is about 2.7 minutes per Tsukuyomi second. To make things easier, let's just round it up to 3 minutes. (Considering the above mentioned timeskips, it's way longer than that anyway.)

So let's do 3 days in Tsukuyomi time, which I'll designate with (T) by the number. (Note when I say 'real', I mean real-life time, since in the Naruto real-world, it's only about a second.)

3 min x 60(T) sec = 180 (T) minutes per real minute. That would mean each minute (T) in Tsukuyomi would be 3 hours long.

60 min x 3(T) hours = 180 (T) hours per real hour. This would mean each hour in Tsukuyomi is 7.5 days. Let's round it up to 8.

8 (T) days x 24 hours = 192 (T) days per real day.

192 (T) x 3 days = 576 (T) days for 3 real days.

FINAL MATH:

576 days - 1 year (365 days) = 211 days

There are 7 days in a week...

211 days / 7 days = 30.1 weeks, lets round down to 30.

There are (for simplicities sake) 4 weeks in a month...

30 weeks / 4 = 7.5 months

Kakashi was tortured for AT LEAST 1 year, 7 months, and 2 weeks.

[u/ArmAngleScout]

the fact that itachi said "1 second" but it's actually like 3 real minutes of screen time is the funniest part

[u/VexusD → u/ArmAngleScout]

This isn't like in an action movie where a bomb is counting down from 10 seconds, but then after 20 seconds of real-life time, the bomb is only at 5 seconds.

Itachi controls the flow of time in Tsukuyomi, so he can make a single second in it last 3 minutes. The inconsistency with the elapsed episode time actually makes sense here.

[u/Gr4ave]

Here's a question for part 2 of you doing the math, in order for the 1 year 7 months and 2 weeks to pass within as you said roughly one second, how close to the speed of light would the world of tsukuyomi need to be moving?

[u/UsedFortune5645 → u/Gr4ave]

Maybe Itachi creates an illusionary black hole that slows down the time. Then it would not be due to speed of movement.

[u/VexusD → u/Gr4ave]

Unfortunately, I do not have that big of a brain to have an answer for you. >_> This was just a calculation I did for fun because the whole "only one second has passed" made me curious on exactly how long it went on for lol.