If you read anything about the Chinese martial arts you will learn that there are external and internal styles. The 'external' styles are 'hard' or depend mainly on 'muscle power' or 'strength'. The 'internal'
styles, on the other hand, are 'soft', 'flexible' and utilise
'internal energy or power' otherwise known as "qi".

External forms

Hei Hu Quan (Black Tiger boxing) is more or less the
same as a Shaolin form, but the creators of hei hu
quan were not monks and the style did not come
from the Shaolin Temple. Hei hu and other
Southern boxing styles are hard fighting arts
practised mainly by the country people of South
East China and influenced to a certain extent
by the geographical and social conditions of
the area.

Nan 18 Luohan Quan (Southern 18 Arhat
boxing) is part of the Shaolin Family system which
embraces a variety of Chinese martial arts styles. 18 Luohan quan was created in Northern Shaolin Temple by the monks who observed different boxing styles of other fighting monks and expressions of the Arhat statues in the Temple. Later they created a style of fighting known as 18 Luohan quan.

Internal forms

Taiji Quan (Tai Chi Chuan) - literally translates as "supreme ultimate boxing" or great extremes boxing," with an emphasis on finding balance between the two great forces of positive and negative. Taiji Quan is a soft and slow martial art featuring circular and flowing movements. Different styles of Taiji Quan stress their own characteristics.

Xing Yi Quan (Hsing-I Chuan), meaning 'form & mind boxing', starts from a standing posture called San Ti, with the body weight mainly resting on the back leg. A Xing Yi Quan fighter uses efficient coordinated movements to generate bursts of power intended to overwhelm the opponent, simultaneously attacking and defending.

Baji Quan (Eight Extremes boxing). This form is performed quickly and aggressively with occasional slow and relaxed movements. There are frequent jumping and twisting techniques. One of the main distinguishing characteristics of Baji Quan form is the fast attacks followed by sudden retreats.