It is a common misconception among lay people that teleportation is a simple matter. Nothing could be further from the truth. Teleportation is an incredibly complex phenomenon, and there are many spells that perform the same fundamental function of moving matter and living energy from one location in space to another through importantly different means.
There are in particular two different subcategories of these spells, namely type of external effect, and duration of intermediate phase. The external effects refer to the effects of the teleportation on the external environment, and must be considered carefully. In unrealistic stories the wizard can just sort of pop randomly about with no effect on the original and final positions of the wizard. This is a foolish depiction.
First let’s look at the external effect types:
Counterbalancing Inversion
This occurs when the space (and all matter and energy within that region) of the original position is swapped with the space of the final position. This is the more common variety and considered the safer, more reliable method. It is however, also more time and energy consuming to perform, as both the original and final positions must be shifted at the same time. In this case, inverting into a space of solid rock should cause the rock to disappear from the final position and appear at the original position.
Plosive Displacement
This occurs when the space of the original position (and all matter and energy within that region) is simply removed and forcefully inserted into the final position. The effect of this is to create a vacuum in the original position that will usually implode kinetically, and a similar explosion of kinetic force at the final position. The advantage of this method is that it is sometimes easier to perform, since only the original position needs to be marked initially. This also allows for intermediate phases as described next. In this case, inverting into a space of solid rock should cause the rock to explode outward. Note that because of the uncertainties of the energy required to displace the rock, such attempts can fail, with potentially disastrous results.
The duration of intermediate phase is also divided into two types:
Instant
Both an inversion and a displacement can be performed instantly. In fact, an inversion must be performed instantly by definition. Such methods do not have intermediate phases and thus require more pre-ritual preparation, such as marking both positions in advance.
Phased
By nature an inversion cannot be intermediately phased, with the exception of the application of a time stop procedure, which case the phased period technically occurs before, and not during the spell. A displacement however can be phased for an extended period of time, assuming an alternate plane can be phased to in a stable manner. This allows for a period of time to occur between the removal of the space from the initial position, and the insertion to the final position. Furthermore, the final position need not be fixed at the onset of the ritual. It is perfectly reasonable to use the duration of the phasing to assess and mark the final position, and in combat situations this can be quite advantageous.
Combat Uses
In addition to the innate utility of near instantaneous movement from one point to the next, teleportation has the added potential value in selecting an appropriate final position to maximize environment side effects. A risky and messy tactic involves teleporting into the middle of enemies using Plosive Displacement. Also known is a tactic that uses the edge radius of a Counterbalancing Inversion like a knife, to cut through things.