lineage is known for their small frame. Their forms and other practice focus on small frame movements, including the old form of Hao Weizhen which they modified for small frame practice. The Li Shengduan lineage also focuses on small frame practice, while the Li Baoyu lineage teaches the old form of Hao Weizhen and advanced techniques in middle frame. Traditional and simplified forms Wu (Hao)-style forms have undergone five stages of development since the nineteenth century, and since the third generation have often been called "kai he" (, ) forms in reference to their focus on "opening and closing" movements. First- and second-generation Forms The earliest written records we have of this style's forms are in Li Yiyu's own hand. In 1881 he recorded a first-generation form consisting of 53 to 55 postures, the count varying as he worked to improve the description. He and his brother Li Qixuan continued working on improvements to the training for the rest of their lives, developing a second-generation 67-posture form. The larger total resulted from separately counting subpostures, such as left and right versions of the same posture, and some additional postures. Among other core tai chi principles, opening and closing movements were emphasized in this style from the beginning, however in the first two generations' forms those were referred to not as "kai he" (, , "open and close"), but with a literary term, "zhuan he" (, . Some have continued to use that older phrase; see the Comparisons section below for more detail on this topic). Third generation: the Kai He form Li Yiyu's top disciple Hao Weizhen created a form that is taught as a sequence of 81 to 88 postures. Hao was the first to use the term "kai he", or "opening and closing", in reference to specific movements in this form, drawing from Li Yiyu's writing on theory (discussed further below). As a result, this has often been called "the Kai He Form" and at times the entire style has been called "Kai He t'ai chi ch'üan". This is the oldest Wu (Hao) form still widely practiced today, and as performed in many schools is still representative of the early forms with its middle frame and its more overtly martial aspects, including many postures with the torso slightly forward-inclined (in line with the rear leg), visible nei jin (internal strength and structure), fa jin (explosive energy), several low