kung-an that gave birth to a whole series   of hua-t'
　　   ous of the "who" type. Some variations on  it  were
　　   "Who is reciting Buddha's name?", "Who is investigating
　　   Ch'an?", "Who is dragging a corpse? " ect.
　　　　  However, many hua-t'ous have no relationship
　　   whatever to kung-ans, but are simply questions
　　   concerning Buddha-nature that either arise spontaneously,
　　   or are assigned by the master as a method of practice.
　　  
　　　　  As we said, the use of the kung-an  or  hua-t'ou
　　   from previous records was not common until the   Sung
　　   dynasty 宋朝, with the  appearance of The Transmission
　　　　 of the Lamp 传灯录. This text contained many
　　   spontaneous kung-ans and hua-t'ous. Fen-yang
　　  
　　   页383
　　  
　　   Shan-chao 汾阳善昭 (947-1024) compiled   a collection
　　   of 100 kung-ans, called Hsien-hsien ipai Chih 先贤一
　　   百则, One Hundred Selections from Previous Sages.
　　   Wu-men Hui-k'ai 无门慧开 (1183-1260) compiled a
　　   collection of 48 kung-ans, called Wu-men kuan 无门关
　　   (Mu-monkan), the Gateless Gate. These all promoted and
　　   encouraged the use of kung-ans.
　　　　  The records of the Ch'an  sect,   including  the
　　   Transmission of the Lamp,  and  the   collections  of
　　   kung-ans, do not frequently refer to tso-ch'an practice.
　　   It was understood that by the time practioners   began
　　   to  ts'an  Ch'an,  they   already   had  a  very  good
　　   foundation  in tso-ch'an.  Such a basis is needed  if
　　   one is to effectively  practice kung-an and hua-t'ou.
　　   Beginners   may  get  some   usefulness   out  of  the
　　   constant  repetition, but  this   will  be similar  to
　　   chanting  a mantra.  Because   the beginner  lacks the
　　   ability to bring his mind to a deep quiescent   state,
　　   it  would   be  difficult,   if  not   impossible   to
　　   experience self-nature or become enlightened.
　　　　  Throughout  Ch'an   history  we read  of advanced
　　   practitioners who visited masters in order   to  assess
　　   their own understanding of Ch'an, or   certify  their
　　   own attainment. These  situations   were  well-suited
　　   for applying the methods of kung-an and hua-t'ou. It 
　　   is important to remember that any interchange between
　　　　 master and disciple can be an opportunity   for  a
　　   live, spontaneous kung-an or hua-t'ou, and that these
　　   practices  should not be thought  of as being limited
　　   to the  sayings  and questions   from  the  historical
　　   record.
　　　　  Ta-hui Tsung-kao 大慧宗杲 (1089-1163) was one of