Chen Style Lao Jia Er Lu, popularly known as Cannon Fist, is usually studied at the advanced level. It is a vigorous empty-hand routine, punctuated throughout with fajing, the relaxed, explosive release of energy typical of the Chen Style. Comprised of forty-three techniques, Cannon Fist trains the Chen Taiji boxer to issue devastating force and technique in a relaxed and coordinated manner. The form also develops chansijing or "silk reeling energy" which is critical to the execution of Chen Taijiquan forms. Cannon Fist is a rare example of the explosive power of Chen Style Taijiquan that emphasizes on speed and power delivered with the style's unique requirements.