Did Ledi Sayadaw invent a vipassana technique? According to the currently available historical sources, did Ledi Sayadaw invent his technique of meditation, or did he learn it in the caves of the Sagaing Hills? Is there enough information to tell which possibility is more likely?
Though there is no definite record who his teacher was, it is said he learned it from someone else when he was in the Monywa region in the side of Lak-pan-taung Mountain. Also there is reference that this is the Traditional Burmese method. This is mentioned in the VRI and pariyatti.org biography. VRI teachers Vipassana as handed down in the Ledi linage. VRI may be drawing on works by Sayagyi U Ba Khin (E.g. The Clock of Vipassana Has Struck page 71 also makes reference to this.) It the strong belief of this tradition (which I also very much involved and practice) that he learned from a linage handed down from the Sona and Uttara who came as missionaries during King Asoka's time.

The Wikipedia entry (originally sourced from On saints and wizards Ideals of human perfection and power in contemporary Burmese Buddhism by Patrick Pranke page 461) mentions Ledi Sayadaw learned the technique of Vipassana which had remained being taught in the caves of the Sagaing Hills.

Hence this was not exactly his creation as per biographical references above. But the book The Birth of Insight in in page 7 says otherwise though. So there is no proper or consistent way to determine what exactly is right,  though previous case may be right. There are parallel of the technique to some extent in other linages too.


  For eight more years he remained there, teaching and continuing his
  own scholastic endeavors, until 1882 when he moved to Monywa. He was
  now 36 years old. At that time, Monywa was a small district center on
  the east bank of the Chindwin River, which was renowned as a place
  where the teaching method included the entire Tipiṭaka, rather than
  selected portions only.
  
  To teach Pali to the bhikkhus and sāmaṇeras at Monywa, he came into
  town during the day, but in the evening he would cross to the west
  bank of the Chindwin River and spend the nights in meditation in a
  small vihara (monastery) on the side of Lak-pan-taung Mountain.
  Although we do not have any definitive information, it seems likely
  that this was the period when he began practicing Vipassana in the
  traditional Burmese way: with attention to Ānāpāna (respiration) and
  vedanā (sensation).


Source: http://www.pariyatti.org/Resources/Treasures/VenLediSayadaw/tabid/205/Default.aspx, http://www.vridhamma.org/Teachers-2 


  Ledi Sayadaw learned the technique of Vipassana which had remained
  being taught in the caves of the Sagaing Hills, which was honeycombed
  with meditation caves and dotted with forest monasteries. For how long
  we do not know. Verbal accounts state that two monks brought the
  practice of Vipassana to this area at the time of the Buddha. It is
  just as likely that prior to the eighteenth century in Burma, as
  elsewhere in the Theravāda world, it was generally believed that it
  was no longer possible to attain enlightenment and hence nibbāna
  through vipassanā or any other means during the present age.
  
  The earliest known challenger to this assumption is that of a monk
  from the Sagaing Hills in Upper Burma named Waya-zawta whose movement
  ﬂourished during the reign of Maha-damma-yaza-dipati (r. 1733–1752). A
  young scholar-monk named Medawi (1728–1816) began writing vipassanā
  manuals in the vernacular. Couched in the language of abhidhamma,
  these are the very earliest ‘how-to’ vipassanā books we possess from
  Burma. Medawi’s earliest manual was completed in 1754. Ledi's lineage
  comes from this line, whereby his main teacher was King Mindon’s royal
  minister U Hpo Hlaing (1830–1883), who was notable for his avid
  interest in western science and eﬀorts to reconcile this new
  perspective with abhidhamma. This synthetic approach was passed on to
  his protégé, the scholar-monk, U Nyana, who later became famous as
  Ledi Sayadaw, arguably the most signiﬁcant promoter of vipassanā in
  the modern period.


Source: http://en.wikipedia.org/wiki/Ledi_Sayadaw, http://journals.ub.uni-heidelberg.de/index.php/jiabs/article/view/9290/3151 (page 461)