The Hidden Meaning
The move in Tai Chi Chuan with the fingers sinking downward, has long been an enigma for many Tai Chi Practitioners.
Conventional self protection ideas popularized have been to use this action as a throw, or joint locking method. this is great as a beginner level understanding and practice method in open classes. Other ideas involve striking the lower abdomen (The Sea of Chi, KI, Prana) with the finger tips, however this would take decades of finger training under severe conditions to be usable in a self protective need. However these will not serve to fully incapacitate the body, and do not reflect the idea of "Grand Ultimate Fist" where as full incapacitation of the opponent lends to this name far better.
When we integrate the knowledge and skill in Kyusho, this "Needle to the Sea Bottom" posture does become fully incapacitating or fatal when applied.This lends more to the "Grand Ultimate Fist" attributes and heritage as well as effect and efficiency long held in the arts more secret training.
Tools, Targets and Trajectory
To gain this secretive level of skill, we need to work with the 3 components of the deadly arts including the tool to be best suited for a deadly target as well as the correct trajectory to inflict massive damage to the opponent. The "Needle" is such a tool when properly used, where as the finger tips are pressed or jammed into a Vital Target... however, unless the correct trajectory (Angle, Direction and End Goal) is employed, the opponent will not be incapacitated. The Target could be one or more of several possibilities, depending on the level of incapacitation or fatal damage one wanted to induce. The trajectory on any of these targets (discussed, taught and demonstrated in the private links below),would be directed toward "The Sea Bottom".
The "Sea" in Tai Chi and all Martial Arts, is in the lower abdomen. This area is called Dan Tien in Chinese based Arts such as Tai Chi, Hara in Japanese (among others in varying cultures). So the meaning of the posture is to strike, press or tear the Viatl Structure by attacking it with enough force downward toward the lower abdomen.
The Hara or lower Dantian, as conceptualised by the Chinese and Japanese martial arts, is important for their practice, because it is seen, as the term "Sea of Qi" indicates, as the reservoir of vital or source energy (Yuan Qi). It is, in other words, the vital centre of the body as well as the centre of gravity.
To learn the targets and see the affect in real time, the full films are located at these links: