How powerful is Homura's shield?


In the anime, Homura is only seen using her shield to reset or rewind time
until the first time she met Madoka.

Can't she rewind time for a minute, or an hour? If she could do it, I think it
would be easier for her to fight against Walpurgisnacht.

And how far is its area of effect? When she was chasing a car, she couldn't
stop time, but only a few parts were stopped and she still had to run to catch
up to it (if she could stop time, she wouldn't need to hurry).

![Homura's shield](https://i.stack.imgur.com/dkPKF.jpg)




According to Gen Urobuchi from his interview in Otona Anime Vol. 20:

> The weapon that looks like Homura's shield is actually a sand timer. When
> the flow of the sand is blocked, time is stopped. And when there is no sand
> on the upper part of the sand timer and then the timer is reverted, one
> month's worth of time is turned back. But before that stage is reached, only
> time stopping is possible. This means the special power of Homura is the
> ability to manipulate one month's time's worth of sand in the sand timer. As
> for the time passed and then turned back, since it was not the focus in this
> work I did not think it through very thoroughly. I think you can say that
> the world split up and became parallel worlds there.

To sum it up:

  * Homura cannot rewind time until one month of time has passed after March 16th, the start of her time loop.
  * Before then, Homura can only stop time and the sand in her sand timer from falling.
  * Homura cannot rewind short periods of time or go forward in time at all.

Besides time, her shield serves the purpose as a probably infinitely spacious
storage for all of her artillery. It should also be noted that her shield is
quite fragile and clearly not a defensive tool. It can be broken as seen in
Rebellion Story when Sayaka stabs the gear mechanism and renders it unusable.
(Then again, this is debatable, as the universe Homura created in her witch
world bended many laws of magic from the normal universe.)

To explain her constant time-stopping when she was chasing the truck in Ep. 6,
one could speculate that she was trying to conserve her magic by periodically
stopping and starting time. Perhaps the truck was moving too quickly for the
small (fixed?) period of time Homura had to move after stopping time. Note
that the average running speed of a human is 8 mph and the truck was probably
moving at about 60 mph, just at the speed limit for trucks on highways in
Japan.




According to Gen Urobuchi from his interview in Otona Anime Vol. 20:

> The weapon that looks like Homura's shield is actually a sand timer. When
> the flow of the sand is blocked, time is stopped. And when there is no sand
> on the upper part of the sand timer and then the timer is reverted, one
> month's worth of time is turned back. But before that stage is reached, only
> time stopping is possible. This means the special power of Homura is the
> ability to manipulate one month's time's worth of sand in the sand timer. As
> for the time passed and then turned back, since it was not the focus in this
> work I did not think it through very thoroughly. I think you can say that
> the world split up and became parallel worlds there.

To sum it up:

  * Homura cannot rewind time until one month of time has passed after March 16th, the start of her time loop.
  * Before then, Homura can only stop time and the sand in her sand timer from falling.
  * Homura cannot rewind short periods of time or go forward in time at all.

Besides time, her shield serves the purpose as a probably infinitely spacious
storage for all of her artillery. It should also be noted that her shield is
quite fragile and clearly not a defensive tool. It can be broken as seen in
Rebellion Story when Sayaka stabs the gear mechanism and renders it unusable.
(Then again, this is debatable, as the universe Homura created in her witch
world bended many laws of magic from the normal universe.)

To explain her constant time-stopping when she was chasing the truck in Ep. 6,
one could speculate that she was trying to conserve her magic by periodically
stopping and starting time. Perhaps the truck was moving too quickly for the
small (fixed?) period of time Homura had to move after stopping time. Note
that the average running speed of a human is 8 mph and the truck was probably
moving at about 60 mph, just at the speed limit for trucks on highways in
Japan.

