Hunch Looking good AD 1279

Korea's violet glow of 25 October 1279 falls in the window for the 1279 to 1280 radiocarbon jump, and the main paper missed it

Miyahara et al. 2022 confirmed a radiocarbon jump between the 1279 and 1280 rings of their conifer (from -12.36 to -9.16 permil) and wrote: 'No auroral activity has been found around 1279 to 1280 CE.' By their own timing rule, the burst must have arrived between about August 1279 and mid 1280.

The Yau, Stephenson and Willis catalogue (1995, entry 291) has a Goryeosa record for 25 October 1279: 'A violet vapour was seen in the west. It was more than 10 chi long. Its light was similar to that of lightning.' We checked the day name: gui-hai falls on 25 October 1279. That is inside the window.

Why it is not yet a finding: one record; violet and western is unusual for an aurora seen from Korea, and 'like lightning' could mean a distant storm. The radiocarbon jump is real in Miyahara's data but smaller or absent in two oak series. Still, this meets our rule for 'looking good': a dated record in the right window, matching a confirmed radiocarbon event, and not in the paper that confirmed it.

Checked in the original text (Goryeosa volume 53): '五年九月癸亥，紫氣見于西方，長十餘尺，光如電'. It is filed among the red omens, while thunder and lightning on nearby days are filed separately as weather, which suggests the court astronomers saw it as a glow rather than a storm. The day falls on 25 October 1279 once the leap month of 1278 is counted. It is also absent from Wang et al. 2021 by design, because that catalogue only lists red glows.

Japan checked 25 October 2026: the Japanese court diaries in the Kokiroku database have no red or white vapour in 1277 to 1282, so Korea's glow remains a single witness.

What to check next

Ask Dr Miyahara whether they considered the 25 October 1279 Goryeosa record (added to the email draft)
Read the original Goryeosa wording for 1279 and its astronomical-treatise context
Check Wang et al. 2021 for any other Korean entries between August 1279 and mid 1280

How it connects

This hunch is about 1279 carbon-14 candidate

This hunch we read it in Hayakawa et al. 2015, Records of sunspot and aurora during CE 960 to 1279 in the Chinese chronicle of the Song dynasty, Earth Planets Space 67:82

This hunch we read it in Hayakawa et al. 2017, Records of sunspots and aurora candidates in the Chinese official histories of the Yuan and Ming dynasties during 1261 to 1644

This hunch we read it in Miyahara et al. 2022, Recurrent large-scale solar proton events before the onset of the Wolf grand solar minimum, Geophysical Research Letters 49 (free to read; read in full 25 Oct 2026; data on figshare doi 10.6084/m9.figshare.17096975)

This hunch is supported by Radiocarbon rise 1279 to 1280: three labs, three sizes

This hunch is supported by The night sky was red, China, 11 September 1277 two years before

This hunch is supported by Red glow in the south, night as bright as day, Korea, 26 March 1278 a year and a half before

This hunch is supported by Violet glow in the west, its light like lightning, Korea, 25 October 1279

This hunch is argued against by Japanese court diaries: no red or white vapour around 1279 Japan saw nothing; Korea's glow stays a single witness

This hunch is supported by Fiery beams around the Northern Crown (Corona Borealis), 1280 weak: doubtful entry, no month, a year late

This hunch came from this step Checked the Yuan and Ming catalogue

This hunch has this hunch or step Checked Fritz for the other candidates too

This hunch came from this step Read the Miyahara 2022 paper Ken found