Bleach Wiki
Shunpo (瞬歩, Flash steps), a movement technique that allows the user to move faster than the eye can follow.[1]. The focal point that determines the basis of this technique is speed. As speed is the main point of the technique the method is best characterized by how fast one can get from point A to point B in the least amount of steps. Training and skill are what determines how fast a user of Shunpo can move; those of little skill in the technique or those who haven't used it an extended amount of time would obviously be out of practice, causing those individuals to be considerably slower, which requires the use of more steps to move the same distance and become winded far easier in a shorter amount of time. The Arrancar variation of Shunpo is Sonído and the Quincy variation of is Hirenkyaku.
In the Bleach universe, shunpo is the most widely used speed technique. Utilizing it takes only a moderate knowledge of Hoho, and it is characterized by the user disappearing from view only to reappear in another location almost instantly.
The most important detail to note is that the speed of shunpo is measured not in miles per second or any similar way. It is measured in the number of steps it takes one to cover a distance. The speed of a shunpo is constant despite rank differences. The perceived difference in speed is when two characters need to reach the same point and one can move a longer distance than the other. Take this example:
Kyoraku and Ukitake are having a race. Kyoraku can shunpo 100 miles in one step, but Ukitake can only shunpo 50 miles in one step.
If they were to shunpo at the same time to a point 50 miles away, they will arrive at the exact same moment. If they were to shunpo at the same time to a point 100 miles away, Kyoraku will only need one step, while Ukitake will need to stop halfway to make another step, thus wasting some time. Kyoraku will then arrive first.
When creating a character who puts an emphasis on speed, claiming to have a 'fast shunpo' is an ineffective way of being 'faster' than an opponent. This only means that you can shunpo an exceptionally long distance, not that you move faster while performing shunpo. You will, theoretically, beat a 'normal' shunpo user to a far away location, but will not be able to start or continue a shunpo more quickly. That is the territory of physical training.
A character who uses shunpo is subject to the same physical limitations as he normally would be. Moving a long distance quickly can be tiring, especially if the shinigami is very heavy or not in good shape, or if they are out of practice performing shunpo. This can somewhat be mitigated by extreme skill in reiatsu control, which will ease the movement. The speed at which one recovers from or initiates a shunpo can also be increased with physical training and conditioning.
