Tangs could be short or long. But, from what I notice from 100+ yo blade, they end up at the grip area.
The grip area traditionally "defined" at the midle of its hilt. But some modern construction blades come with huge moment of inertia. Then, martial artists, practitioners and also masters have to compensate by hold it a bit closer to its CG.
Here 's some pic of real cutting.
http://www.geocities.com/mooyim_9999/webpage/killer.htm