  In this article, we present the results of the surveys on sunspots and
auroral candidates in Rikkokushi, Japanese Official Histories from the early
7th century to 887 to review the solar and auroral activities. In total, we
found one sunspot record and 13 auroral candidates in Rikkokushi. We then
examine the records of the sunspots and auroral candidates, compare the auroral
candidates with the lunar phase to estimate the reliability of the auroral
candidates, and compare the records of the sunspots and auroral candidates with
the contemporary total solar irradiance reconstructed from radioisotope data.
We also identify the locations of the observational sites to review possible
equatorward expansion of auroral oval. These discussions suggest a major gap of
auroral candidates from the late 7th to early 9th century, which includes the
minimum number of candidates reconstructed from the radioisotope data, a
similar tendency as the distributions of sunspot records in contemporary China,
and a relatively high magnetic latitude with a higher potential for observing
aurorae more frequently than at present.
