  We review some applications of the method of electronic searching for
historical observations of sunspots and aurorae in the Chinese text corpus by
Hayakawa et al. etc. However, we show strong shortcomings in the digital search
technique as applied by them: almost all likely true sunspot and aurora records
were presented before (e.g. Xu et al. 2000), which is not mentioned in those
papers; the remaining records are dubious and often refer to other phenomena,
neither spots nor aurorae (this also applies to Hayakawa et al. 2017c). Most of
the above publications include very few Chinese texts and translations, and
their tables with abbreviated keywords do not allow the reader to consider
alternative interpretations (the tables also do not specify which records
mention night-time). We have compared some of their event tables with
previously published catalogs and found various discrepancies. There are also
intrinsic inconsistencies, misleading information (lunar phase for day-time
events), and dating errors. We present Chinese texts and translations for some
of their presumable new aurorae: only one can be considered a likely true
aurora (AD 604 Jan); some others were selected on the sole basis of the use of
the word "light" or "rainbow". Several alleged new aurorae present observations
beside the Sun during day-time. There are well-known comets among their
presumable aurorae. We also discuss, (i) whether "heiqi ri pang" can stand for
black spot(s) "on one side of" or "beside" the sun, (ii) aurora color confusion
in Hayakawa et al. (2015, 2016), and (iii) whether "white" and "unusual
rainbows" can be aurorae.
